4. Matt Mervis
Matt Mervis had a six-week long stint in the majors this year and it did not go well at the plate. In 90 at-bats, Mervis had a .167 batting average with 3 home runs and a .531 OPS. The 25-year-old is a plus defender at first base but needs refinement at the plate.
When he was sent back down, Mervis worked on subtle swing adjustments that yielded good results in Triple-A. By the end of the season, Mervis had collected 22 home runs, 23 doubles, and an impressive .932 OPS for the Iowa Cubs.
It remains to be seen whether these adjustments will transfer well to MLB but the Cubs could sure use a home-grown left-handed slugger.