Blake Treinen Diagnosed With Stress Reaction In His Back

The Athletics are shutting down right-hander Blake Treinen for the remainder of the regular season due to a back issue, manager Bob Melvin announced after today’s game (Twitter links via Susan Slusser of the San Francisco Chronicle). MLB.com’s Martin Gallegos tweets that Treinen has been diagnosed with a stress reaction in his back.

The issue has been bothering Treinen for the past three weeks, it seems, and it’s reached the point where he requires some downtime. It’s worth noting that the team has not yet formally ruled Treinen out for a postseason run, though that’ll surely depend on how his back responds to this shutdown. In his absence, the A’s are moving Chris Bassitt into a long relief/piggyback role, per Slusser, and seemingly going with a rotation consisting of Sean Manaea, Mike Fiers, Tanner Roark, Brett Anderson and Homer Bailey.

It’s been an ugly season for Treinen, who stepped up as one of baseball’s premier relievers almost immediately upon being traded to Oakland at the 2017 deadline. The now-31-year-old posted 38 innings of 2.13 ERA ball with a 42-to-12 K/BB ratio down the stretch for Oakland in ’17 before turning in a ridiculous 0.78 ERA (1.82 FIP) with 11.2 K/9, 2.4 BB/9 and a 51.9 percent ground-ball rate in 80 1/3 innings last year.

Treinen, however, lost his grip on the closer’s role in 2019 and has generally struggled since a late-April meltdown against in Toronto. His regular season will come to a close with a 4.91 ERA (5.14 FIP, 5.02 xFIP), 9.1 K/9, 5.7 BB/9, 1.38 HR/9 and a 42.8 percent grounder rate. Treinen’s average velocity, swinging-strike rate, opponents’ chase rate and opponents’ hard-hit rate have all trended sharply in the wrong direction, leaving the A’s with somewhat of a decision in the offseason; he’s due a raise on this year’s $6.4MM salary in his final offseason of arbitration eligibility. For a team with the type of payroll constraints the Athletics face each year, that could be viewed as a steep price to pay for a rebound candidate.

The Athletics, now 92-61 on the season, have won eight of their past 10 games and now hold a 2.5-game lead on the top Wild Card spot in the American League. There’s still time for the Rays and/or Indians to overtake them, but the A’s are in a fairly commanding spot with regard to the AL Wild Card race at this point. Their schedule the rest of the way features three home games against the Rangers, two on the road against the Angels and four on the road in Seattle.