Nationals Claim Matt Krook, Designate Andre Granillo

The Nationals announced that left-hander Matt Krook has been claimed off waivers from the Athletics.  To create roster space for Krook, the Nats designated right-hander Andre Granillo for assignment and optioned righty Zak Kent to Triple-A Rochester.

The A’s designated Krook for assignment just yesterday, and Krook joins Tom Cosgrove and Karl Pilkington as left-handed bullpen adds for the Nats just within the last few days.  Mitchell Parker is set for Tommy John surgery and Richard Lovelady is also on the 15-day injured list, depleting the relief corps of two prominent left-handed options.  Krook will step right into the active roster in Kent’s place, giving Washington three southpaws (Krook, Carson Palmquist, PJ Poulin) in its current relief mix.

More substantive bullpen additions might be coming before the trade deadline, since the Nationals need a lot of relief help in general and the team has remained a surprise contender in the wild card race.  The front office’s approach for now could be to just patch holes, and wait a few more weeks to see if the Nats can keep it up and remain in position for the club to be deadline buyers of some measure.

Krook has gotten cups of coffee in each of the last four MLB seasons, with 12 innings pitched over his 13 career games.  The small sample size has been ugly, as Krook has a 16.50 ERA during his brief time as a big leaguer that includes a 17.18 ERA over 3 2/3 frames with the Athletics this year.  Krook has 12 walks against only 13 strikeouts in the majors, as the control problems that plagued the lefty in the minors have only grown more severe in the Show.

Since becoming a full-time reliever in 2023 when pitching in the Yankees’ farm system, Krook’s numbers have improved, and he posted a 3.72 ERA, 30.9% strikeout rate, and 11.8% walk rate across 29 innings with Triple-A Las Vegas this season.  Most impressively in that hitter-friendly environment, Krook hasn’t allowed a home run, as he has continued his career-long trend of keeping the ball in the park and generating grounder rates of well over 60% (61.4% this year).

Between this extreme groundball ability and the strikeout rates he has generated in the minors, it is easy to see why teams keep taking fliers on Krook.  At age 31, it remains to be seen if Krook can translate any of his success in the minors to even moderate production in the big leagues, as MLB hitters have thus far had no trouble figuring him out.

Granillo is another of the many pitchers in Washington’s bullpen churn this season, and the righty posted only a 9.64 ERA over 9 1/3 innings, with eight walks and two homers allowed across eight appearances.  A career reliever, Granillo’s excellent work with Triple-A Memphis in 2025 earned him his first big league promotion with the Cardinals, but a February trade to Washington hasn’t worked out at all for the right-hander.  In addition to Granillo’s struggles in the majors, he also has a 6.82 ERA in 31 2/3 frames with Rochester.

It was enough for the Nationals to send Granillo to DFA limbo.  He hasn’t been outrighted in his career, so Granillo will have to accept an outright assignment to Triple-A in the probable event that he clears waivers.