Week 3 is supposed to be the week where we start to actually learn things. And in some cases it was. We learned, or were reminded, that the Chiefs offense simply can't be stopped. We also learned that a rookie quarterback is ready to play in the NFL. 

Did we learn that one of our top 20 receivers can't be trusted? Or which defense is the free space for tight end production? These are the questions we'll answer in this week's Believe It or Not. I've also got your answers with Twitter polls on each subject. 

Daniel Jones should be added in all leagues.

It's hard to imagine a more impressive debut for a rookie signal caller. Jones threw for 336 yards and two scores, while adding 28 yards and two scores on the ground. He was the No. 2 Fantasy quarterback in Week 2 and led the Giants to their first win of the season. it was the best performance by a rookie quarterback in his debut for Fantasy eever.

For those of us who mocked the Giants pick on Draft Day, every indication we've gotten since says they made the right pick and we were wrong. Jones' was composed against the blitz and reminded us what he can do with his legs as well. Giants fans and Fantasy players should be excited

Verdict: Don't believe it. 

This is not an indictment of Jones. He was extremely impressive. But with the bye weeks starting, I'm not going to be carrying two quarterbacks on most of my rosters, especially when I'm not starting one of them for the next month. The Giants face Washington in Week 4, the Bears in Week 5 and the Patriots in Week 6. The only matchup I'd even consider using Jones in is the next one against Washington and I'd like to see a little bit more before I trust him in my lineup. Especially since he'll be playing at least a few weeks without Saquon Barkley, one of the best receiving backs in the league. 

You'll want Jones on your roster in Week 7 when he faces the Cardinals, but it's not worth stashing him for three weeks at this time of year.

Mecole Hardman and Demarcus Robinson are must-start until Tyreek Hill returns

For the second week in a row Hardman and Robinson both scored touchdowns and will finish as top-25 receivers. Robinson made a spectacular one-handed catch in the end zone and finished with three catches for 43 yards. Hardman only caught two passes, but one of them went 83 yards for a touchdown, so two was plenty. Somehow Patrick Mahomes has been even better than he was in 2018 and you just need to start anyone catching passes from him. Well, except Sammy Watkins I guess.

Verdict: Don't believe it. 

I know this is counterintuitive. I don't even feel comfortable saying it. But what these two receivers have done is not sustainable. And it's really not likely that they continue this production, even until Hill returns. 

Hardman and Robinson are getting around five targets per game the past two weeks. Even at Mahomes' historic efficiency that only projects at about 45 yards per game and a 50-50 shot at a touchdown. Yes, they've scored five touchdowns between the two of them the past two weeks but Sammy Watkins and Travis Kelce have combined for one in that same stretch. It will likely even out.

This is not to say you can't start these two receivers. They're exactly the type of boom-or-bust options you want on your team to start when you have no one else you feel comfortable with. Just don't force them into the lineup. It's unlikely they keep this up.

Alexander Mattison is the most valuable handcuff in Fantasy.

Mattison had a fantastic game on Sunday, rushing 12 times for 58 yards and scoring his first NFL touchdown against the Raiders. He's averaging better than five yards per carry on the season and has proven himself worth of the Latavius Murray role in this offense. Mattison is still owned in fewer than 60% of leagues and that needs to change when waivers run this week.

Verdict: Believe it. 

This has very little to do with Mattison has done so far. Mike Zimmer and the Vikings would like to be a run-heavy team and through three weeks they're accomplishing that with ease. They averaging just 21 pass attempts per game. With Dalvin Cook healthy that makes Mattison a boom-or-bust flex at best. But Cook still hasn't made it through a full season healthy. What more could you want from a handcuff than what you're getting here? It's a run-first offense paired with a fantastic defense and an injury-prone running back in front of him. There is no better handcuff in Fantasy.

Stefon Diggs should be benched until the Vikings play a good offense.

The flip side of all that running and defense in Minnesota is what it's doing to their passing game. In three games Diggs has just 12 targets. He's caught six of them for 101 yards and a touchdown. That's a good game for a top-20 receiver, not a three-game stretch. Mike Zimmer has installed the offensive coordinator he wants and Kevin Stefanski is doing things the way Zimmer prefers. There will be weeks where Diggs reaches the end zone and he may even have a big game against the right matchup, but you can't trust Diggs right now.

Verdict: Believe it.

Kirk Cousins threw 21 passes on Sunday. That's also how many passes he's averaging per game. It won't always be this easy for the Vikings, but their next two games are against the Bears and the Giants, so it's hard to imagine them opening things up any time soon. As talented as Diggs is, there's no reason you would feel comfortable with him in your starting lineup. 

Start any tight end against the Cardinals.

This is getting ridiculous. In Week 1 T.J. Hockenson faced the Cardinals. He was the No. 1 tight end in non-PPR. In Week 2 Mark Andrews found the same result. In Week 3 it was Greg Olsen's turn and once again, he was the best tight end in non-PPR. I'm not one to lean too much into positional defense, but this is too much to ignore. If you're streaming tight end this is your free pass.

Verdict: Believe it. 

Will Dissly gets the Cardinals in Week 4. He's widely available. He's also the clear top streaming option in Week 4. This is part me buying into what the Cardinals are doing against tight ends, and part me just thinking the defense is bad overall. Dissly is the No. 3 option in Seattle's offense and may be No. 2 some weeks. I don't believe he'll be the No. 1 tight end and continue the streak next week, but he should absolutely be a starter.