Jairo Diaz

After a promising 2015 campaign, Diaz missed all of 2016 while recovering from Tommy John surgery and tossed only five big-league innings over the next two seasons. In 2019, he re-emerged with Colorado and showed that he could still throw flames, averaging 97.0 mph on his fastball and posting an above-average strikeout rate (25.7%) and walk rate (7.8%). Though hitters registered an 89.8 mph average exit velocity against Diaz, he yielded a palatable 1.09 HR/9 by limiting opponents to a 31.3% flyball rate. The right-hander finished the campaign with a mediocre 4.53 ERA but improved as the season wore on, posting a 3.07 mark over his final 26 outings. Diaz was effective while filling in as a joint closer late in the season, notching five saves without allowing a home run after Aug. 20. He's likely to slide back into a setup role in 2020 but could be first in line for save opportunities should an opening arise.

Diaz impressed in his first cup of coffee with the Rockies in 2015, raising hope that he could become a major cog in the bullpen very quickly. Those plans were quickly sidetracked, however, after he tore the UCL in his right elbow early in spring training, keeping him out for the entirety of the 2016 campaign. The right-hander's rehab seems to be going as scheduled, and considering the fact that his Tommy John surgery occurred so early in 2016, there's a decent chance he'll be ready to go by midseason. Diaz is only 25 years old, so if he can continue to throw in the upper-90s following the surgery and operate at the high level he displayed at the end of 2015, he could work his way into a prominent back-end role.

After being acquired in December in a trade with the Angels, Diaz was sent to Triple-A after struggling in spring training. He pitched decently with the Isotopes, but he really came into his own once he was called up to the majors in August. In 19 innings, the right-hander had a 2.37 ERA and a 1.16 WHIP with 18 strikeouts. He also was used more in high-leverage situations later in the season. Diaz appears to have gained the trust of manager Walt Weiss, and if he can continue to pitch as well as he did at the end of 2015, the 24-year-old should be a major part of the Rockies' bullpen plans this year and in the future.

Diaz got the call to make his major league debut in September after excelling at Double-A Arkansas, posting a 2.20 ERA with a 48:10 K:BB ratio in 32.2 innings. His success continued in his cup of coffee with the big club in the final month, as he notched a 3.18 ERA in 5.2 frames. Diaz has been finding his strikeout pitch the last two seasons, which is exactly what you want to see from a 23-year-old who can exceed 97 mph with his fastball. He also kept his walk rate below 3.0 BB/9 in 64.2 innings split between High-A Inland Empire and Arkansas last season. Diaz might be a long shot to earn an Opening Day roster spot in 2015, but he'll have a slightly clearer path to the big leagues after being acquired by the Rockies via trade in December.