For the past two seasons, Stammen has "put up" and solidified his place in the big leagues. He's done so by becoming something uncommon, yet valuable to a modern bullpen.
From 2012-13, the right-hander has gone 13-7 with a 2.54 ERA and nearly a strikeout per inning. But lots of relief pitchers are effective. Not many do so while taking on Stammen's workload.
His 170 innings pitched over the past two years are the most for any Major League pitcher who hasn't started a game, topping Colorado's Adam Ottavino by nearly 13 innings. While his ERA during that span ranks eighth among pitchers with 100 innings, nobody else above him on the list logged more than 130. Stammen also led the Majors by completing 49 outings of at least two innings, during which he posted a 1.63 ERA.
"I take pride in taking care of my body and being able to pitch every day," said Stammen, who turned 30 on Sunday. "I've been lucky to have a pretty resilient arm. It is a point of pride for me. I like being the workhorse, the bulldog. I think those are good qualities to have in the bullpen. It's a good thing to look back on the last two seasons, so hopefully I continue that the next couple seasons."
Thirty years ago, multi-inning ace relievers were common. From 1982-83, 22 relievers topped 170 total innings without starting a game.
But that number has dropped drastically over the years as bullpens have become bigger, more specialized and more reliant on matchups. While teams often do carry a long reliever, it's usually for the purpose of having somebody available to soak up innings in the event of a blowout, long extra-inning game or a starting pitcher getting knocked out early.
Stammen can do those things, but also has been effective enough to throw a single inning late in a close game when needed.
"Any time you have a guy like that out of the bullpen, it's a very good thing to have, a very strong tool to have, and not a lot of teams have that," said fellow Nats reliever Tyler Clippard, who went through his own journey from starter to long reliever to setup man.
In converting to the bullpen, Stammen underwent a transformation.
As a starter in his rookie year, he relied heavily on a four-seam fastball, with a curveball as his primary breaking pitch. These days, he goes after hitters primarily with a sinker and slider, with the curve as a third pitch. According to manager Matt Williams, Stammen's ability to throw any of those for a strike and generate quick outs with the sinker allows him to "roll through innings pretty quick."
Stammen, who said he never had prototypical mechanics, also decided to embrace his natural tendency to throw across his body rather than constantly try to stay on a perfect line. The motion adds some deception his delivery without compromising his ability to hit his spots.
The starter background, the refined repertoire and the delivery helped Stammen produce performances like the two he authored against the rival Braves last season in Atlanta. On May 31, he came in for an injured Stephen Strasburg in the third and threw four perfect innings, getting the win as the Nats prevailed, 3-2. On Aug. 17, he entered a tie game in the 12th and tossed three scoreless frames, picking up another "W" when Washington took a 15-inning victory.
"It does a lot of things," Clippard said of Stammen's ability to stretch out. "Obviously, it takes some of the workload off some of the guys that might have to pitch in some of those types of games that maybe they needed day off or whatever the case may be. But more importantly what it does is it keeps us in games."
Williams said that Stammen is likely to fill a similar role as he did the past two years under Davey Johnson. On Wednesday, he threw two innings and started a third in his fourth outing of the spring, building toward that point.
At this point, could Stammen build all the way back up to a starting rotation at some point?
"I think it's still in the back of my head that I wish I could do that," he said. "But again, on this starting staff, it's not going to happen. That ship has sailed with the Nationals. If I ever started again, it'd be for another team, but hopefully I'm with this team my whole career and I have a long, lustrous career in the bullpen."