WASHINGTON -- When the news came at the Winter Meetings in 2018, the first reaction for most was a simple question: Who is Tanner Rainey?
Tanner Roark was known. He spent six seasons pitching for the Nationals, bouncing between the rotation and bullpen, and being involved in some of the stranger storylines within the team (such as Moldgate in Chicago).
When he was traded for Rainey -- hours after Mike Rizzo said nothing was imminent with Roark -- deciphering why the move was made became the next step. Roark was a solid, if declining, starting pitcher. Rainey was an erratic Triple-A reliever.
Part of it had to do with money. Part of it had to do with potential -- the kind that has landed Rainey as the team's setup man, more or less, and second-most important reliever in 2020.
Roark's next contract would be around $10 million. The Nationals didn't want to pay that much. Rainey threw 100 mph -- with ease -- though he often didn't know where his throws would finish. And, of course, the team could always use more bullpen help.
Rainey was called up in early 2019 because the Nationals had no choice. He was a clear part of the bullpen in 2020. Seven games into this season, he's made five appearances. Sean Doolittle's velocity and effectiveness have receded. Will Harris is on the 10-day injured list.
Daniel Hudson is throwing 97 mph, so he seems intact. Rainey has been effective in all his appearances. It's those two at the back of the Nationals bullpen for now.
Rainey, like almost everyone else on a mound this season, says he is not working with his regular velocity. His fastball is 95.4 mph, according to Fangraphs, down from 97.8 last year. That velocity will return. How Rainey manages his slider will have more of an impact on his future outcomes.
"I'm in a good place with it, but not exactly where I'd like to be," Rainey said. "There's been some times this year where I needed to throw it in the zone for a strike and wasn't able to execute. I've gotten away with it so far, but throughout a full season that's not the case. You can't get away with stuff the entire year. So not being able to get it in the zone all the time when I need to could pose an issue. But so far it feels really good. I feel like the break is there. It's got the action that I'm looking for and just continue to improve on the command of that and everything should be good."
Rainey has also toiled with a changeup of sorts -- something he more labels a modified split-finger pitch. He needs to throw with two fingers on the ball. He can't get a comfortable grip otherwise. So, Rainey has to figure out an approach to a changeup with that in mind. But, don't expect to see it in a high-leverage situation.
"If I found that that pitch was serviceable at all..it's a different look," Rainey said. "One more thing to have in your back pocket if you ever need it."
Which is how Rainey has evolved for Davey Martinez. He was an in-case-of-emergency-break-glass option in the past. Now, he's one of the most important people in the bullpen.
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Tanner Rainey zips from unknown to crucial Nationals bullpen piece originally appeared on NBC Sports Washington