Biggest MLB surprises and busts

Castellanos was a very good prospect and quality player early in his career for the Tigers, but he's brought his game to a different level early in 2016. After hitting .255-15-73 last season, he's started this year hitting .321-10-32 for the Tigers.

Alvarez signed a one-year deal with Baltimore late in the offseason, and he still hasn't gotten his bat going. He's hitting just .214-4-13 in 37 games.

Chatwood's return from Tommy John surgery has gone great, as he's been Colorado's ace. The right-hander is 6-4 with a 2.99 ERA in 11 starts, quite an accomplishment for a Rockies pitcher.

Arizona had high hopes for Corbin as its No. 3 starter after a good second half of 2015, but he's been inconsistent. The lefty has a 4.96 ERA in 11 starts, allowing 11 long balls in 65.1 innings.

Diaz has replaced the injured Jhonny Peralta at shortstop for the Cardinals and emerged as a front-runner for NL Rookie of the Year, hitting .328-7-26 in 180 at-bats. Not bad, especially considering that he hit just .278 in the minors last year.

Fielder successfully returned from a neck injury last season, but he's struggled this year. The big first baseman is hitting only .190-3-28 in 52 games.

A minor league veteran, Duvall is making the most of his first opportunity as a regular this season. He has 14 home runs and an .878 OPS in 49 games.

Despite his struggles at the plate last season, there were high hopes that Gomes would rebound as one of the top catchers in the AL. That hasn't happened, as he's hitting only .171-6-26 in 41 games.

Gomez looked like a middle reliever entering the season, but he's emerged as one of baseball's top closers. He leads the league with 17 saves and has an excellent 2.89 ERA for the surprise Phillies.

Houston paid a hefty price to acquire Gomez from Milwaukee at the trade deadline last year, but he hasn't hit since his arrival. He hit only .242-4-13 in Houston over the final two months of 2015 and has been far worse this year at .182-0-5 with 53 strikeouts in 37 games and one DL stint.

Herrera had a good rookie season in 2015, but he's taken his game to a different level this year. The leadoff man already has more walks than he had all of last season, resulting in a .419 on-base percentage.

Greinke received a $206.5 million contract from the Diamondbacks in the offseason but has been very mediocre. He's 7-3 with a 4.29 ERA in 12 starts, struggling to keep the ball in the park.

Hill made four great starts for Boston at the end of last season, and the veteran parlayed that success into $6 million this offseason. He's making the A's look like geniuses with his early performance, going 8-3 with a 2.25 ERA and more than 10 strikeouts per nine innings.

Harvey has been serving up batting practice for much of this season, with a 5.37 ERA in 11 starts. A mechanical adjustment in late May does look like it might have fixed his issues.

The seventh pick in the 2014 draft, Nola was projected as a safe middle-of-the-rotation starter but now looks like an ace. He has a 2.88 ERA and 0.93 WHIP in 11 starts, with a terrific 5.85 strikeout-to-walk rate.

Jones has been a streaky hitter early on, and the product has been a poor .242-7-26 line for the O's. His .693 OPS is easily the worst of his career as far as full seasons go.

Pomeranz pitched in relief for most of last season with Oakland, but he's moved back to the rotation full time this year and thrived for San Diego. He has a 2.48 ERA and 10.7 strikeouts per nine innings.

The trade that sent Miller from Atlanta to Arizona this offseason looks more lopsided every day. Miller has been arguably baseball's worst pitcher, going 1-6 with a 7.09 ERA in 10 starts. He's now on the DL with a finger injury.

Returning from a major knee injury, the expectations for Saunders were low. He's been great for Toronto, hitting .295-9-19 in 176 at-bats.

Morales rebounded to have a great season for KC in 2015, but he's had a slow start this year. The DH is hitting only .197-6-22 in 183 at-bats.

Story got off to an incredible start this season while replacing Jose Reyes. He's among the league leaders with 15 home runs.

After signing for $217 million, Price was roughed up in April with a 5.76 ERA. He pitched slightly better in May and continues to miss bats, so statheads aren't worried.

Traded by the Astros at the end of spring training and then waived by the Padres, Straily has been Cincinnati's only reliable starting pitcher. The right-hander has a 3.43 ERA in 60.1 innings.

Puig has seemed to be a better citizen for the Dodgers this year, but it hasn't helped him on the field. After struggling last season, he's hitting only .237-5-20 in 53 games this year.

Baltimore knew Trumbo had plenty of power when it acquired him, but he's exceeded most expectations starting the year hitting .288-17-42 in 52 games.

Detroit signed Upton to a six-year deal in the offseason, but he's been a monstrous bust early on. He's hitting just .215-3-12 and leads the AL in strikeouts.

Acquired in the offseason as a placeholder for top shortstop prospect Orlando Arcia, Villar has been terrific for the Brewers. He's hitting .305 and leads the NL with 19 stolen bases.

It's been a frustrating start for Votto, who looks lost at the plate. He's hitting only .222 through 54 games.

Wright was just considered rotation depth entering the year, but the knuckleball pitcher has been Boston's most reliable starter. He has a 2.45 ERA in 10 starts.

After winning 17 games with a 3.38 ERA last season, Wacha has struggled in 2016. He has a 4.99 ERA in 11 starts.