Mariners reinstate Mitch Haniger from COVID list, designate Matt Koch for assignment

The Mariners announced Friday that they’ve reinstated right fielder Mitch Haniger from the Covid-related injured list and designated righty Matt Koch for assignment in order to open a spot on the active and 40-man rosters.

Haniger, who paced the Mariners with 39 home runs in 2021, was out to a slow start in eight games before he tested positive for COVID-19 on April 16. Haniger missed nearly two weeks’ time and 11 games, and earlier this week told reporters that he was still not quite back up to 100% (Twitter link via Daniel Kramer of MLB.com). He’s apparently back in playing shape now and will return to the lineup and look to improve upon the .176/.200/.471 slash he posted through his first 35 trips to the plate.

The return of Haniger will only deepen a Mariners lineup that has been among the most productive collective units in Major League Baseball so far. The M’s rank eighth in the majors with 88 runs scored and have the game’s third-best wRC+ at 123, indicating their lineup has been 23% better than average on the whole. Seattle hitters currently lead the Majors with an 11.1% walk rate, and they’re seven in home runs even without Haniger’s powerful bat. He’ll slot back into the outfield/designated hitter mix and ought to jump right back into the heart of the batting order.

Koch, 31, appeared in four games with Seattle and pitched 4 1/3 innings. He allowed four runs on five hits (two homers) and a walk, striking out three hitters along the way. Koch has appeared in parts of five big-league seasons, all coming with the D-backs prior to his Mariners debut this season. He was a serviceable arm out of the Arizona bullpen from 2016-18, pitching to a 4.04 ERA — albeit a mark that was not supported by the underlying metrics. Koch’s 13.9% strikeout rate and 1.72 HR/9 mark during that time were both considerably worse than the league average.

The Mariners will have a week to trade Koch, place him on outright waivers or release him.