This season's most surprising and disappointing MLB players

Alonso was the Mets top hitting prospect coming into the year, but he wasn't expected to make the team out of spring training. Not only did he make the team, but the powerful first baseman hit 30 home runs during the first half. He also won the MLB Home Run Derby, adding $1 million to his bank account.

The reigning AL MVP, Betts is having a good year by MLB standards but not nearly what was expected after last year. The leadoff man is hitting just .272-13-40 with 10 steals at the break after winning the AL Batting Title and slugging .640 last year.

Bell hit only 12 home runs for the Pirates last year, but he's been a different player after adjusting his swing in the offseason. The Pirates first baseman is hitting .302-27-84, leading the league in RBI and also doubles (30).

A career .289 hitter, Cain hit just .246 in the first half likely due in large part to a thumb injury. Overall, he has a poor .660 OPS, which is his worst since 2013.

Bellinger regressed last year after winning the NL Rookie of the Year in 2017. After some offseason adjustments, he's turned into a true star hitting .336-30-71 with a league-leading 70 runs scored. He's neck-and-neck with Christian Yelich for the NL MVP.

The entire Cardinals offense has disappointed in the first half, and Carpenter leads the way. After hitting a career-high 36 home runs last season, Carpenter is hitting just .216-10-28 in 77 games during the first half.

A quality offensive player with back-to-back 20 home run season before this year, Escobar has hit like a star early this year. Playing primarily at third base, he's hitting .296-18-67 for the surprising Diamondbacks squad.

Foltynewicz's year started with some arm trouble, and he's yet to find himself. Through 11 major league starts, he has a 6.37 ERA and was demoted to Triple-A in late June. The Braves need Foltynewicz to get right if they want to make a run in the playoffs.

A former top prospect, Giolito was nowhere close to reaching his potential before this season. He finished last year with a 6.13 ERA in 32 starts, but his ERA is down nearly three runs this year to 3.15. He also leads the AL with 11 wins and has 120 strikeouts in only 100 innings.

Freeland finished fourth in the NL Cy Young voting last year, finishing with a 2.85 ERA despite pitching his home games at Coors Field. He wasn't the same early this year, posting a 7.13 ERA in 12 starts before getting demoted to Triple-A. Freeland should be back in Colorado soon, but it remains to be seen which version he will be.

LeMahieu was set to serve as a utility man for the Yankees this season after leaving Colorado, but he's been much more. He currently leads the NL with a .336 batting average and also has 12 home runs and 63 RBI. It's as if he never left Coors Field.

Signed away from Japan last year, Mikolas immediately became the Cardinals ace with 18 wins and a 2.83 ERA in 32 starts. The results have been much different this year, as Mikolas has a 4.53 ERA in 18 starts at the break.

Signed to a three-year, $30 million contract with the Rangers this offseason, Lynn was more of a flier after posting a 4.77 ERA last season. He's shown signs of dominance with Texas this year, with 11 wins, a 3.91 ERA and 4.73 K/BB ratio during the first half. His 2.97 FIP shows a possible ace during the second half.

The Phillies aren't getting what they hoped for from Harper after signing him to a 13-year, $330 million contract in the offseason. He hasn't played terribly, but Harper's .253-16-62 first half is hardly great, and he also failed to make the All-Star team for the first time since 2014.

Coming off a nice second half last year, Marte has developed into a full blown star this year. He's hitting .311-20-53 and leads the NL with 110 hits. His 20 home runs is already a career high, and he's also made a nice adjustment to the outfield.

It's hard to find an explanation for how badly Ramirez has performed relative to the last two seasons. He hit .270-39-105 with a .939 OPS last season, but the third baseman is hitting just .218-7-35 with a .652 OPS in the first half.

Means was a back of the rotation prospect coming into this year, but he's been a true ace for Baltimore during the first half. The lefty has a 2.50 ERA in 82.2 innings during the first half and made the All-Star Game in his rookie season.

The son of Hall of Fame catcher Ivan Rodriguez, Dereck had a breakout rookie season with a 2.81 ERA over 118.1 innings for the Giants. The results have been much different this year, as Rodriguez has a 5.27 ERA in 56.1 innings and has been shuttled between Triple-A and the majors.

Minor had a great second half for the Rangers, and has continued to perform this year. The lefty has a 2.54 ERA in 18 starts, posting nearly one strikeout per inning. Now in his eighth MLB season, the lefty made his first All-Star appearance.

Despite back-to-back 30 home run seasons, Shaw gave Milwaukee no choice but to demote him to Triple-A with his poor first half performance. He hit just .164-6-13 in 212 plate appearances for the Brewers.

Polanco showed signs he could hit in the past, but he's shaping up to be a legitimate AL MVP candidate. He hit .312-13-42 with 57 runs scored during the first half, and has also played excellent defense.

It's been an inconsistent first half for the 2018 AL Cy Young winner. Snell has 122 strikeouts in 90 innings, but he also has a 4.70 ERA, nearly three runs higher than last season. The poor pitching started after he suffered a freak toe injury.

Ryu posted a sub-2.00 ERA in 15 starts last season, but few thought he could maintain that level over the long term. He's been even better in the first half, with a 1.73 ERA in 17 starts due in large part to just 10 walks in 109 innings.

It's been one injury after another for Stanton during the first half. He's appeared in only nine games due to triceps, shoulder, calf, and knee issues. Nearing age 30, this year is a bad sign for the Yankees, as Stanton is signed through 2027.