Midseason Review of Minnesota Twins Preseason Top 10 Prospects

#8: Adalberto Mejia, LHP, Minnesota
The Minnesota Twins capitalized on the hot first half of Eduardo Nunez in 2016 to trade him to the San Francisco Giants for Mejia, knowing he could move quickly. Mejia was really finished with his minor league development when he was acquired, having already worked his way to the cusp of the Giants’ rotation.
Mejia doesn’t have overpowering stuff, but from the left side, he has a low-90s sinking fastball, plus change, and also works with a curve and slider that are average to above-average pitches, giving him a four-pitch mix that allows him to be effective for at least two trips through a lineup each time out, and even more on the days when his breaking ball(s) is really working well.
Mejia opened the season in the Twins rotation and was sent to Rochester when there was no need for a 5th starter for a couple weeks, but he’s primarily been in the Twins rotation this season, throwing 58 1/3 innings, with a 4.32 ERA, 1.51 WHIP, and 29/48 BB/K ratio. While those numbers are not elite starter numbers, there is room for growth there for a guy to be an excellent inning eater that works in the #4 spot of a rotation and saves the bullpen.
Mejia has thrown enough to disqualify himself from prospect lists going forward and should be a certain portion of the rotation going forward.
#7: Lewin Diaz, 1B, Cedar Rapids
Diaz only appeared on 4 of the 10 lists I looked at, and only John Sickels at Minor League Ball had Diaz ranked outside of #10 as I did, ranking him #6 in the Twins system. Perhaps we talked with the same scout who saw him in Elizabethton, but considering the guy I talked with was a scout with the Atlanta Braves, that’s unlikely.
Diaz has a pretty left-handed power swing that is reminiscent of former Twin David Ortiz. While the two have little in common physically, the swing is certainly notable. Yes, they’re roughly the same height, but Diaz’s roughly 210-220 pounds on his frame are lean and cut, certainly not bearing a resemblance to the future Hall of Famer.
I mentioned that Diaz does possess athleticism and the plus arm to profile in a corner outfield spot, but at his size, he’s likely to stay at first base just due to future physical growth to come. After showing excellent contact skills and good zone judgement in the Appy League in 2016, Diaz has seen his walk rate dip below 5%, however, he has also kept his strikeout rate under 15% on the season.
Yet, in spite of seemingly swinging at near everything coming to the plate, Diaz is putting up a .286/.320/.468 line with 24 doubles and 10 home runs in 79 games. He is very possibly the most polished power hitting prospect in the system currently, and it would not surprise if he was the guy who took over in Minnesota when Joe Mauer’s contract is up after the 2018 season.