SSS rank among all right-handed relief pitchers in the system: 16
Diaz gets a mulligan for a lost 2018 season, which would have been his first full one in the White Sox system. As of last May, Diaz was dealing with shoulder issues per GM Rick Hahn, and those issues lingered all season, as the righthander was on the IL from Opening Day to the end of the season at Winston-Salem.
At the time of the Chris Sale trade, as the least-known asset among Michael Kopech, Yoán Moncada and Luis Basabe, Diaz was considered a lottery ticket. He got a late start and didn’t start playing professionally until he was 21, for one of the Red Sox’s Dominican teams.
In 2016, Diaz made a quick jump from the DSL to Boston’s Low-A league team in Greenville, and in 60⅓ innings, he walked 25 and struck out 63 for a 3.88 ERA and 3.19 FIP. In 2017, Diaz’s injury woes began, as he opened the season on the Kannapolis injured list and basically pitched one week in late May (six games, 6.75 ERA) before a second IL stint, and a July (post-draft) promotion to Winston-Salem. With the Dash, Diaz was worse, giving up 19 hits and 19 earned runs in 12 innings, losing control of the zone as well (12 walks, 14 Ks). It’s safe to assume that Diaz was trying to pitch through injury for all of 2017.
Per Prospects 1500, Diaz works consistently in the upper 90s and can hit 100. He works from a three-quarters slot, and has some pretty inconsistent secondary pitches. In other words, he’s a typical White Sox development staff project.
The White Sox may have had some designs on stretch Diaz out as a starter, but his injury woes will shelve that experiment, at least in the short term.