Every year, baseball fans know not to overreact to players who start off hot. We're so starved for anything to sink our teeth into that we'll throw good sense to the wind and declare a player a bust or a stud based on a good month, because it's all we have to go on. 

And sometimes, those breakthroughs in April hold up. Gerrit Cole posted a 1.76 ERA in April this season and hasn't looked back, and Lorenzo Cain has similarly proven capable of holding up a new level of production hinted at in the first month. Other potential breakout stars from April haven't exactly had the same luck, however. 

Some of these players showed new skill sets that could have made you believe they were reaching a new level, but were unable to sustain those improvements. Others were just getting lucky for a few weeks, and were all bound to fall off. let's take a look at some of the biggest from around the diamond to see where they've gone wrong since their fast starts.

Stephen Vogt, C, Athletics
April rank: #1 C
Ranking since: #8 C

After the first month of the season Vogt was arguably the best hitter in the American League, ranking first or second in OPS, batting average, slugging percentage and RBI as of May 5. At this blog, I facetiously asked "Where will Stephen Vogt put his MVP trophy?" I didn't actually expect him to remain the top catcher in baseball, I did say he could hit .280 with 15 homers from May 5 on. He has eight homers in 81 games since, a solid pace, but his average has plummeted to .226. Part of that can be blamed on a lower-than expected BABIP, and he is still a top-10 catcher in Roto leagues since, so it's hard to complain too much about someone you probably drafted with your last pick, if you did at all.

Adrian Gonzalez, 1B, Dodgers
April rank: #1 1B
Ranking since: #16 1B

At this point in his career, any breakout would obviously be unexpected for Gonzalez, so it wasn't hard to shrug off his April, at least to a point. Still, the fact that he is just 16th among first basemen in Roto scoring since May 1 is definitely a surprise. His .270/.351/.452 line in that time is pretty much identical to what he did last season, so that should probably be your expectation moving forward. Unlike some of the other players on this list, Gonzalez's best days are almost certainly behind him. 

Devon Travis, 2B, Blue Jays
April rank: #2 2B
Ranking since: #40 2B

Travis' April success was largely fueled by his six homers, which pushed him from the lower rungs of the Blue Jays' prospect ladder to the top of Fantasy owners' wishlists. Injuries aside, he hasn't actually been bad since May first, with a very solid .290/.340/.420 slash line in 40 games that certainly plays at second base. However, the power he showed in that first month just wasn't real. He averaged 17.5 homers per-162 games in the minors, a very solid mark for a middle infielder, but not what his April hinted at. Travis can very well be a top-10 option at 2B if his health ever improves, but those six homers in April might stand as the best total for a month for as long as his career runs. 

Marcus Semien, 3B, White Sox
April rank: #5 2B, #3 SS
Ranking since: #31 2B, #27 SS

Expectations were pretty high for Semien coming into the season; Semien was one of Al Melchior's favorite breakout candidates coming into the season, as a solid power-speed combo who showed improved plate discipline during a late-season callup. However, his strikeout rate has gone back over 22 percent for the season, and that has played a big part in his dropoff. He is hitting just .248 since May 1, and his seven steals and homers haven't been enough to make up for it. He's become surprisingly easy to drop. 

Matt Carpenter, 3B, Cardinals
April rank: #2 3B
Ranking since: #15 3B

Carpenter has had a few different seasons all rolled into one this season already. In April, he looked like an MVP candidate; from May 1 through July 29, he flirted with the Mendoza line and saw his power disappear like last season. Now, in 12 games since, Carpenter has clobbered seven homers and looks like an elite hitter again. He is safely worth considering a top-10 3B, but it's surprising how streaky he has been this season.  `

Wil Myers, OF, Padres
April rank: #6 OF
Ranking since: #180 OF

It's hard to get a bead on Myers, who has alternated between looking like a star and a scrub throughout his career. And injuries haven't helped. He was hitting .291/.340/.493 on May 10, but a wrist injury has limited him to just three games since. You can't blame him for his ranking here, but it's not hard to view him as injury prone after a second season in a row spoiled by wrist issues. 

Jake Marisnick, OF, Astros
April rank: #7 OF
Ranking since: #165 OF

Based on his minor-league track record, Marisnick's best-case scenario always looked a lot like what he managed in April. He had a little power -- eight extra-base hits in 17 games started -- and stole eight bases, and avoided strikeouts well enough that an average in the .270's wasn't out of the question even when his BABIP corrected itself. He has started just 58 games since May 1, and it's hard to argue he has been worth even a role that big, with a .479 OPS to his name. With the acquisition of Carlos Gomez, there's nowhere for him to play right now, and it's fair to wonder if Marisnick will ever hit his upside -- and whether that upside is even all that high for Fantasy. 

Matt Kemp, OF, Padres
April rank: #9 OF
Ranking since: #45 OF

Kemp was one of the best hitters in baseball over the second half of last season, and the fact that he was able to pick up right where he left off was a very promising sign. He had a .326/.357/.478 triple-slash line as of April, and it seemed fair to assume that the power would come along later. And that power has come, as he has 11 homers in 91 games since May 1. Unfortunately, that also comes with a pitiful .237/.290/.376 triple-slash line, an elevated strikeout rate and little hope for improvement. Kemp is a tremendously streaky hitter, so he could turn things around before long. It's hard to bet on it at this point, however. 

Jake Odorizzi, SP, Rays
April rank: #14 SP
Ranking since: #88 SP

Odorizzi has always shown promise, so his April kind of looked like he was figuring everything out, especially when he kept it going through the end of May. However, he suffered an oblique injury in June and has not been quite as sharp since; his 4.31 ERA over his last seven starts is a lot closer to what Odorizzi did last season. Still, he has a low-3.00's FIP for the season and his K rate is climbing up, so there's a lot to like about what Odorizzi is doing.  

Anthony DeSclafani, SP, Reds
April rank: #11 SP
Ranking since: #146 SP

DeSclafani was never a big-time prospect, so his April success never seemed totally sustainable. In fact, a .176 BABIP pretty much screams "unsustainable." He has a 4.42 ERA in 18 starts since May 1, and is probably more of an NL-only Fantasy option looking ahead in his career. 

Bartolo Colon, SP, Mets
April rank: #12 SP
Ranking since: #136 SP

Colon is 42. What, did you think he was breaking out all of a sudden? Come on. He may be nearing the end of a very long career. 

Edinson Volquez, SP, Royals
April rank: #17 SP
Ranking since: #54 SP

Because he was able to sustain a low-3.00's ERA last season, it wasn't crazy to expect more of the same from Volquez, especially with arguably the best defense in baseball behind him. However, there isn't much margin for error with Volquez because of his middling strikeout rate and relatively high WHIP, which is why he drops out of the top-50 among SP since May 1 despite a pretty solid 3.59 ERA. 

Ubaldo Jimenez, SP, Orioles
April rank: #19 SP
Ranking since: #91 SP

I never bought Jimenez's "return to form." Jimenez has actually managed to sustain a K/9 over 8.0 since May 1, and has improved his walk rate, but the results just haven't been there, because he has become more hittable when it comes to both regular hits and homers. Jimenez can still show flashes of being a good pitcher, but I'm through trusting him to sustain; at 31, he is who he is.