Mariners claim Sean Doolittle off waivers, DFA Keynan Middleton

Like the old adage says: When one closer disappears, another closer appears

To Doo, or not to Doo; that is the Key question.

Well, no. It’s not. It’s all been done.

Keynan Middleton, whom the Mariners had optioned to Tacoma yesterday, joins Rafael Montero as another high-visibility off-season bullpen acquisition to be DFA-ed mid-season. Though Middleton’s difficulties weren’t quite as disastrous as Montero’s, his strong early outings had become fewer and farther between as of late.

Meanwhile, acquiring Sean Doolittle has long felt all-but-inevitable for the Seattle Mariners, given Jerry Dipoto’s bullpen rototiller and the how well Doolittle and his wife seem to align with the city overall. The Extremely Online (and Twitter-beloved) bespectacled reliever has had a middling go of it this season, with a 4.46 ERA and 5.47 xFIP in 38 innings of work. A late free agent signing in February of this year, Doolittle, now 34, had a proven track record of success in the bullpen, but struggled in both 2019 and 2020. Some at FanGraphs posited it was a combination of injury issues and overwork, which led to a precipitous drop in his velocity.

Doolittle trained and rehabbed his oblique in Arizona this offseason – though he had initially planned to work at Driveline Baseball in Kent – and signed with the Reds for $1.5 million and miscellaneous incentives. He had an up-and-down start this season, but seemingly more careful usage and a lowered arm angle prompted a return to 95-97 MPH in the last few weeks, as reported (paywall) by Bobby Nightengale. He’s been particularly effective against lefties this season, and does come with playoff experience, if you care about that sort of thing.

It’s unlikely that we’ll see Doolittle in a traditional closer role, or even in many high-leverage situations initially, but he’s a low-risk pickup for the Mariners and an extremely high-reward person for the city of Seattle.

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