Former Angels pitcher impresses in Mariners ST debut as he competes for a role on the team

The Mariners have signed a former Angels pitcher to a Minor League deal. After an impressive debut, let's see where he could pitch in 2024 for Seattle.

Seattle Mariners Photo Day
Seattle Mariners Photo Day / Steph Chambers/GettyImages

Spring Training is a great time to see prospects play. Today I saw two pitchers throw at least one no-hit and two strikeout innings: Jackson Kowar and Jhonathan Díaz. Díaz threw two of these innings with a total of four Ks. I wanted to learn more about one of the newer faces on the Mariners.

Jhonathan Diaz just joined the Mariners about two-and-one-half weeks ago, signing a minor league contract as a free agent. He is currently on the roster for the Tacoma Rainiers. I like our current rotation as well as our bullpen. We have already heard that two relievers may have injuries with Matt Brash and Gregory Santos taking it slow.

Depending on his performance for the rest of Spring Training, his left-handed pitching might help the team in Seattle. Root Sports commentators interviewed Cal Raleigh who spoke highly about the ways Jhonathan varied his pitches in terms of type, speed, and height.

Jhonathan Diaz is a Left-Handed Pitcher

Jhonathan is a native Venezuelan and began playing in the United States in the Red Sox system when he was 17 in 2013. In 2020, he signed as a free agent with the Mariners’ AL rival, the Los Angeles Angels. He was a free agent after last season, and is entering his age-27 season.

Jhonathan is a LHP, which is something the Mariners are short on at that big-league level. In the past, he has been both a starting and relieving pitcher. Right now, the Mariners have many RHPs in Seattle and the pipeline. The starting rotation consists only of RHPs now that Gonzales and Ray are gone. Gabe Speier and Tayler Saucedo are the sole lefties in the bullpen. Tacoma has two LHPs, including Díaz, and AA Arkansas has three lefties. I think that we may see Jhonathan at T-Mobile Park this season.

The most likely scenario for Díaz coming to Seattle would be if Saucedo or Speier were unable to play. Jhonathan might also join the bullpen if other relief pitchers were injured, depending on how he performs for the time in the Minors.

Jhonathan Díaz and the Angels

In his three years with the Angels, Jhonathan shuttled back and forth between Anaheim and their AA team, the Rocket City Trash Pandas in Alabama, and the AAA Salt Lake Bees.

In 2021, Díaz pitched 13 innings for the Angels: two games as a starter and one as a reliever. He had an ERA of 4.15. With the Rocket City Trash Pandas, he had a win-loss record of 5-3 in 61 innings pitched. He started nine games and pitched four games in relief. His ERA was 3.98.

Díaz pitched 15 innings for the Angels in 2022, starting three games and relief pitching in one. His ERA was .293. He was a starting pitcher in 10 games for the Salt Lake Bees. His win-loss record was 3-1. He had an ERA of 4.98.

When Díaz played for the Angels this past season, his performance declined. He started one game and was a relief pitcher in three. He threw only seven innings with an ERA of 10.29. In AAA, however, Jhonathan pitched 87 innings with nine wins and two losses, throwing as a starter and reliever. He had an undisclosed injury halfway through the 2023 season but apparently is healthy and ready to go. He looked that way today!

Several of the 2023 pitchers from AAA are no longer on the team: Darren McCaughan (MIA), Diego Castillo (TEX), Matt Festa (SDP), Easton McGee (MIL), Justin Topa (MIN), Trevor Gott (OAK), Penn Murfee (ATL). Tommy Milone, Jose Rodriguez, and Marcus Walden are free agents. I imagine that Jhonathan would fit into the starting rotation in Tacoma unless the manager specifically wanted him to be a reliever.

His Future with the Mariners

ESPN already has Jhonathan Diaz listed as a starting pitcher for the Mariners. I anticipate, however, that he will start in Tacoma with the Rainiers. Depending on how he does in Spring Training (that first game was a great debut), will determine where he ends up. Time will tell. I am excited for the season! Go, Mariners!