Draft prep season for Fantasy Football is supposed to be when optimism reigns. Especially when it comes to your early-round picks, who are supposed to be the rocks upon which you build your team. We spend a lot of time talking about what a player's best-case scenario looks like because that's what ultimately wins you your league -- and oftentimes, it's as simple as just pointing at what a player did in 2020.  

Of course, while sometimes, players live up to or even surpass expectations, it's just as likely that any given player might underperform too. Last season, first-rounders like Christian McCaffrey, Ezekiel Elliott, Saquon Barkley, Michael Thomas, Joe Mixon, Miles Sanders and Josh Jacobs all disappointed us, and not all because of injuries. That's not as much fun to talk about, but it's still important to have an idea in your head of how things can go wrong. 

Because it's not the same for everyone. I mean, sure, everyone could just get hurt and wreck their season, but that's not the point of this exercise. The point of this exercise is to look at the non-injury ways a player's season could get derailed. From some limitation in their own game to some overlooked flaw in their situation, the point of this two-part series -- players ranked 1-12 in ADP are here -- is to try to figure out what it might look like when things go wrong. Here's what that would look like for the most likely second-round picks in 2021 drafts.

13. Nick Chubb

How things could go wrong: The offense around him regresses

You can't say everything went right for Chubb in a season where he missed four games, but … pretty much everything else went right for him. When you rush for 5.6 yards per carry and score a touchdown once every 15 carries, things probably went right for you. The Browns offense started clicking after a slow start, and it certainly helped that their offensive line missed just seven games between them for the whole season. Can you count on that again? 

How likely do I think things are to go wrong for Chubb? Chubb's profile is very similar to Derrick Henry's in a lot of ways, which means his margin for error is relatively small. Even with his outrageous efficiency in 2020, Chubb couldn't break the top six in points per game if you take out the game he left early with injury. That was probably a lot closer to a best-case scenario than anything else, so I can easily see a scenario where Chubb is a solid, steady contributor, but not necessarily a superstar. It's also hard to see how things go too wrong, though. There's a nice high floor. 

14. Stefon Diggs

How things could go wrong: Josh Allen takes a big step back

Diggs finally got his opportunity to be an alpha WR, and he proved more than up for the task. However, he also benefited from Josh Allen taking an almost unprecedented leap in production as a passer. And, anytime you see someone take as big a step forward as Allen did -- his TD% was 69% higher than his first two seasons while he leaped from 3,089 passing yards to 4,544 -- you should expect some natural regression. How likely do I think things are to go wrong for Diggs? One thing that helps Diggs' case is that this was clearly a symbiotic relationship -- Allen played better in large part because he had a reliable superstar receiver to lean on. I'm going to guess he leans on Diggs again, and while I do expect some regression for Allen, Diggs is still a top-three WR for me. 

15. Antonio Gibson

How things could go wrong: The passing game role never materializes

Gibson ran the ball very well in 2020, but he's still learning some of the finer nuances of the position. He should continue to be the lead back, and it's not unreasonable to expect something like 250 carries for him this season. However, unless he can get into that 50-catch range, his ceiling is likely capped unless he can have another outlier touchdown season like he did as a rookie, and you shouldn't bet on that. Gibson needs to push J.D. McKissic for a solid share of the passing work to have the true breakout we're hoping for. 

How likely do I think things are to go wrong for Gibson? This is becoming more of a concern for me, as Gibson has logged just one third down snap through two preseason games. Obviously, you can catch passes on first and second down, but if Gibson is still being viewed as a two-down back, it's going to be hard to get a much bigger role than what he had as a rookie, when he caught 36 passes. It's too early to say definitively that he won't have that role, but I'm certainly less sure of it now than I was before preseason action started up, because I was mostly just assuming there was a significantly larger passing game role coming. That may not be the case. 

16. Najee Harris

How things could go wrong: The offense collapses around him

There's always uncertainty around how rookies will play and how they will be used, but we're pretty confident Harris is going to be at least pretty good while having a sizeable role. The problem is, this is a revamped offensive scheme built around a 39-year-old quarterback who, frankly, looked pretty finished the last time we saw him. Running back circumstances matter so much, and there's a decent chance Harris is stepping into a pretty rough circumstance. 

How likely do I think things are to go wrong for Harris? I'm very concerned about Roethlisberger at this point. He looked hesitant to sit in the pocket and risk getting hit to let plays develop last season, and if he continues to play that way, it's going to make things easier for the defense to play the run game and short-area passes more aggressively. We've seen glimpses of Harris' impressive playmaking so far in preseason, and as long as this offense is just average, he should be a top-12 RB. But there's a chance things go really, really wrong here. 

17. DeAndre Hopkins

How things could go wrong: The Cardinals spread the ball around more

Hopkins had an excellent bounceback campaign, and he did it on the strength of both improved efficiency and yet another huge target share. However, Kliff Kingsbury's offense is designed to spread the field and make it tougher for the defense to focus on any one player. The additions of A.J. Green and Rondale Moore could give the Cardinals two more viable options in the passing game, limiting their need to lean so heavily on Hopkins. 

How likely do I think things are to go wrong for Hopkins? Of course, both Green and Moore are sort of hypothetical contributors at this point. Green was one of the least efficiency receivers in the NFL last season, while Moore has a ton of talent but is also a rookie who struggled mightily to stay healthy in college. I like Moore's potential in this offense especially, and I think he could be good for the offense as a whole, but he's also no guarantee to be a threat to Hopkins' dominance. 

Sony Michel was traded to the Rams. What does this mean for Darrell Henderson? And for Michel? Adam Aizer and the crew you covered on a Fantasy Football Today emergency pod breaking down the trade:

18. Calvin Ridley

How things could go wrong: There isn't enough volume

Ridley is expected to step up as the true No. 1 WR for the Falcons, after serving as more of a 1b last season, so how could volume be a concern? Well, Ridley got his 143 targets on 628 pass attempts by the Falcons, so if new coach Arthur Smith brings in a more run-heavy approach and Kyle Pitts is the kind of playmaker we think he could be, maybe there isn't that league-leading target potential we're hoping for. 

How likely do I think things are to go wrong for Ridley? Though that still wouldn't be enough to chase me off Ridley. The Falcons will likely still have to throw a ton, and Ridley is a proven elite playmaker who figures to see an enormous share of air yards yet again -- he led the NFL by over 200 yards last season. With a significant, downfield-oriented role, Ridley seems like a shoo-in for top-six production in my eyes. 

19. DK Metcalf

How things could go wrong: There aren't enough big plays

We're still not quite sure what the Seahawks new-look offense will actually look like, but the hints we've gotten suggest a faster pace and more short throws after a pretty deliberate, downfield-first approach throughout Metcalf's career. Metcalf has thrived as a big-play receiver, making up for a relative lack of volume, but if there are going to be fewer deep shots, will he get enough additional targets or break enough long catch-and-runs to make up for it? 

How likely do I think things are to go wrong for Metcalf? Metcalf is pretty capable of taking a slant to the house, so he doesn't need to just beat the defense over the top. He isn't the most proven short- and intermediate-area target, but he's so physically dominant that it would be silly to bet against him at this point. And I'm not actually sure we're going to see a significant reduction in deep passes, because Russell Wilson is so good at throwing them and Metcalf (and Tyler Lockett) are so good at making plays on them. It would be taking away one of their offense's strength. If anything, more short area targets might make Metcalf more consistent, while he still has that big-play ability. 

20. Joe Mixon

How things could go wrong: The offense never comes together

For Mixon, it's never been a question of talent. In fact, if you are on the "#NeverMixon" train, it's likely because you spent a few too many years betting his talent could overcome his situation. I'm operating under the assumption his situation has changed for the better, especially following the departure of Giovani Bernard this offseason. However, the offensive line may still be a significant problem, and reports out of Bengals camp suggest Joe Burrow hasn't quite hit his stride yet. What if the situation Mixon finds himself in just isn't any good -- again?

How likely do I think things are to go wrong for Mixon? I'm confident in Mixon because I believe the passing game role will finally be there. However, that's certainly not a guarantee, and if Samaje Perine or Chris Evans start to get passing downs opportunities, it will severely hamper Mixon's upside. You can still be a good Fantasy back in a bad offense, but if he's not getting a significant amount of targets, you're relying on him to rack up yards and touchdowns in a bad offense, which is a bad bet. 

21. Clyde Edwards-Helaire

How things could go wrong: He loses too many goal-line and third down touches

So, what happened in 2020, basically. Edwards-Helaire got those opportunities early on but just wasn't particularly effective and eventually started ceding those opportunities. It's hard to know what to make of his playoff usage given that he was coming off a pretty serious injury, but he was giving up a lot of valuable snaps to Darrel Williams, and now Jerick McKinnon is drawing strong reviews for his work in the passing game in training camp. Edwards-Helaire sure didn't look like a difference-making talent in 2020, but this can still be a difference-making opportunity. It's just not clear he's earned it. 

How likely do I think things are to go wrong for Edwards-Helaire? I'm higher on Edwards-Helaire compared to other running backs than the consensus, but I rarely take him because I'm more excited about the wide receivers or tight ends I can take at the same point in the draft. So, let's say I'm cautiously optimistic, but not exactly willing to bet on it based on what I've seen. 

22. Darren Waller

How things could go wrong: He has more target competition

That's it? Waller has established himself as one of the premiere playmakers at the tight end position, and an argument can be made that he belongs in his own tier, below Kelce but above George Kittle. However, that case gets a lot harder to make if Henry Ruggs and Bryan Edwards take the steps forward the Raiders clearly believe they are capable of taking. Waller jumped from 117 to 145 targets last season, and while he can still be a difference maker at tight end with the lower number, he wouldn't be worth this price. 

How likely do I think things are to go wrong for Waller? I think it's pretty unlikely -- I'm higher on all three of the top tight ends than nearly anyone else. They are the biggest potential edge you can get outside of the top three running backs, and I wouldn't be opposed to taking any of them in the top 15 picks. That being said, the Raiders don't seem like they ever want to be a pass-heavy team, so if Ruggs and Edwards do take that step forward, Waller's chances take a hit, for sure. 

23. Justin Jefferson

How things could go wrong: Adam Thielen remains the go-to option in the red zone

The expectation is that Jefferson will take the lead across the board in the Vikings passing game. He probably won't be able to sustain last season's 11.2 yards per target number, but if he pushes up into the 140-target range and scores more than his seven touchdowns from 2020, he can more than make up for it. However, even down the stretch when it became clear Jefferson was the better player, Thielen scored three touchdowns on 32 targets over the final five games. What if there's a bit of Julio Jones in Jefferson's game. 

How likely do I think things are to go wrong for Jefferson? I'm not buying it. Jefferson is the better player, and that should be the case between the 20s and in the red zone. He's going to be one of the very best wide receivers in the NFL for a long time, and he's a big reason why I'm pretty much out on Thielen at this point. 

24. A.J. Brown

How things could go wrong: His knees just aren't right

This one is starting to become a real concern. Brown had offseason surgery on both knees and has been held out of practice recently as a result of an injury to one of them. That's a bad sign, even if all indications are that the present knee injury isn't anything to be too concerned about. However, that it's already become an issue without even appearing in a game is a pretty big red flag. 

How likely do I think things are to go wrong for Gibson? I tend to be less concerned about injuries than most Fantasy analysts, but that comes with a caveat: Present injuries are to be taken very seriously. We're not very good at quantifying and acting on injury risk based on past injuries, but when a player is currently dealing with something, it can be easy to just dismiss it as something that will be fine come Week 1. I'm not panicking about Brown, but I did move him behind Allen Robinson in my WR rankings this week. He'll start to slide down draft boards soon. 

So which sleepers, breakouts and busts should you target and fade? And which QB shocks the NFL with a top-five performance? Visit SportsLine now to get Fantasy cheat sheets for every single position, all from the model that called Josh Allen's huge season, and find out.