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2021 Angels Player Review: Jhonathan Diaz

The Stay Was Short, But Diaz Flashed His Abilities On The Mound For The Angels While Building His Confidence For The Future

Los Angeles Angels v Seattle Mariners Photo by Steph Chambers/Getty Images

After spending seven years in the Boston Red Sox farm system (2013-2020), Jhonathan Diaz signed a minor league contract with the Angels on November 17, 2020. Prior to joining the Angels roster in September, the Valencia, Venezuela native began 2021 with Double-A Rocket City pitching in 13 games (nine starts). The southpaw went 5-3 with a 3.98 ERA and 78 Strikeouts through 61 innings.

On May 13, Diaz pitched against the Tennessee Smokies (Chicago Cubs affiliate), picking up the win after tossing 5.2 shutout innings, while yielding just one hit. The most impressive thing from his line score that night was the 11 batters he retired via the strikeout. This was a career-best performance in strikeouts, that had only gone as high as nine on four different occasions. Oddly enough, two-in-a-half months later (July 22) against the same Smokies, Diaz would replicate another 11-strikeout performance, while securing the win and tossing five quality innings. Here are all 11 strikes from the July 22 game:

Following his second 11-strikeout performance, Diaz put himself in the franchise history book for the Rocket City Trash Pandas in his very next start on July 29 against the Birmingham Barons (Chicago White Sox affiliate). He tossed the first ever complete game by a Trash Panda pitcher (at Toyota Field), spinning nine innings and allowing only two runs on six hits with seven strikeouts.

Diaz was promoted to Triple-A Salt Lake on August 26, where he made three starts before his major league promotion on September 17. He picked up the spot start against the Oakland Athletics, though the outing turned short as Diaz got the hook from manager Joe Maddon in the second inning. The A’s tabbed the lefty for two runs on two hits in 1.2 innings, but with nerves playing a factor, command was Diaz’s big struggle, walking four and striking out only two. Before the season concluded, Diaz got one last chance to impress in a starter’s role on October 2 against the Seattle Mariners. He took a no-decision for his efforts, but the performance provided more length, going 4.1 innings and allowing three runs on six hits with only two walks and three strikeouts.


3 Games / 2 Starts / 1-0 Record / 4.15 ERA / 13 Innings Pitched / 9 Strikeouts / 7 Walks / 1.38 WHIP / .220 Opp Avg. / 11 Hits Allowed / 6 Runs Allowed / 1 Home Run Allowed

*With Angels (MLB)

16 Games / 12 Starts / 5-6 Record / 4.01 ERA / 76.1 Innings Pitched / 92 Strikeouts / 20 Walks / 1.11 WHIP / .229 Opp Avg. / 65 Hits Allowed / 34 Runs Allowed / 5 Home Runs Allowed

*Combined stats with Rocket City (AA) & Salt Lake (AAA)

  • Made MLB debut on September 17 at Angel Stadium vs. Oakland A’s


Diaz is a five-pitch pitcher who utilizes his top-three pitches (Changeup, Slider and Sinker) more than 97% of the time. He does not blow you away with velocity, however his effectiveness especially with his Slider makes him a well-balanced pitcher keeping opposing hitters on their toes. The Slider is used second-most in the arsenal (29.1%), garnering the most attention with its low Opp Average (.222) and high Whiff percentage (37.5%). Looking at his splits through the 13 innings he pitched, Diaz found great success in lefty versus lefty matchups. Holding left-handed batters to a sub-one batting average (.059) and 0.88 WHIP with five strikeouts.


With only three appearances to his name in 2021, it’s ironic that his best performance took place on a whim on September 25 at Angel Stadium against the Seattle Mariners. The game was originally started by Jaime Barria, however, the right-hander was removed from the game after the second inning due to right shoulder impingement. With a 3-0 lead entering the game in the third inning, Diaz sprung into action and was lights out all night long. After yielding a run in the third on a J.P. Crawford groundout, Diaz settled down and shut out the Mariners for the remainder of the game. He retired 16 consecutive batters at one point (between the 3rd and 8th inning) until a two-out double by catcher Cal Raleigh. This appearance was a great stepping stone for Diaz to get experience at the big league level, especially in a low pressure situation as the Angels defeated the Mariners by the final score of 14-1 on Fan Appreciation Day.


Diaz is among many young Angels pitchers that saw their debuts happen in 2021, but this may not necessarily mean they will be returning on a full-time basis in 2022. With the Angels front office looking to retool the pitching staff this offseason (starting and relief), it seems likely that Diaz will begin 2022 in the minors with Triple-A Salt Lake. Based on the depth of pitching already on the active roster and the additions that are on the horizon, the lefty can continue his development in the minors and be a fresh arm during any point of the season. His contract does in fact favor the Angels since rookies under club control make just $575,000 AAV per/year, so there are plenty of options before a final decision must be pinned down.