John Lannan has filled in admirably when called upon, and he'll continue to do so in Strasburg's spot the rest of the regular season. But those are the four young pitchers who will become the faces and arms of the Nats' first postseason push.
If Strasburg's highly publicized shutdown cast a shadow over the Nationals' successful season, Zimmermann, Gonzalez, Jackson and Detwiler are the ones primed to step out of it in late September and into October.
Along with Strasburg, the most effective starting rotation in baseball has been comprised of the steady right-hander from Wisconsin, the hard-throwing lefty with the contagious smile, the durable righty who won a World Series last fall and the skinny, shaggy-haired southpaw with a sinking fastball and expanding arsenal.
Separate the names from the numbers, and separate the rest of the rotation from Strasburg, and you'll find a group that still matches up with any in baseball despite its relative lack of experience -- Jackson is 29, the others are all 26 -- and national exposure.
Zimmermann and Gonzalez have earned their share of attention in the baseball world. Zimmermann was formerly the Nats' top prospect and quickly made his way to the Majors, although he hasn't posted high win totals -- he finished under .500 in 2011 despite a 3.18 ERA -- or racked up strikeouts with 100-mph fastballs, like Strasburg. He simply goes about his business, impressing those who take the time to watch him work.
"He competes. He doesn't care. He's not afraid. He comes after you," pitching coach Steve McCatty said when asked earlier this season to describe Zimmermann, who is 10-8 with a 3.01 ERA. "He does what he does, and he doesn't change. It's not like he's a plodder, but he's a plodder -- more like a racehorse, a thoroughbred. That's what he is. That's what you love about him."
Gonzalez was also a former top prospect and a two-time All-Star who put together two big years in Oakland before getting dealt to Washington for four prospects. While he broke out in 2010 and '11, the fun-loving lefty is putting together his best year yet with the Nationals, increasing his strikeouts, decreasing his walks and giving up home runs at an absurdly low rate (0.4 per nine innings) en route to a 2.95 ERA.
All that has put Gonzalez in the discussion for the National League Cy Young Award, and he could become the Majors' first pitcher to 20 wins the next time he takes the mound. But for as friendly and outgoing as he can be off the field -- catcher Kurt Suzuki says the Hialeah, Fla., native with a contagious smile can have fun anywhere he goes -- Gonzalez rarely draws attention to himself with his comments to the media, usually deflecting praise toward his teammates.
"When you start looking at one thing, it drives you crazy," Gonzalez said recently about becoming the franchise's first 20-game winner since 1978. "If it comes, it comes, but at the same time, I'm looking further than that. I want to continue to contribute to this team."
Beyond Zimmermann and Gonzalez, there are "The Other Guys" -- Jackson and Detwiler. That nickname caught on when Detwiler revealed a picture hanging above his locker at Nationals Park after one of his recent starts. It's a poster promoting the Will Ferrell/Mark Wahlberg buddy-cop film of the same name, only with Detwiler and Jackson's faces in place of the movie's stars.
Indeed, Jackson and Detwiler have mostly flown further under the radar this season, but their contributions have hardly gone unnoticed or unappreciated by the Nats.
Signed to a one-year, $11 million contract this offseason after pitching for the World Series champion Cardinals last fall, Jackson has made the occasional brilliant start en route to a 3.89 ERA and the best strikeout-to-walk ratio (2.94) of his career.
Detwiler, however, has been the biggest surprise. A first-round pick in 2007 who's completely changed and rebuilt his delivery, Detwiler currently carries a 3.16 ERA identical to the one next to Strasburg's name. He is 10th in the NL in that category, and his 2.86 ERA since the All-Star break ranks first among Nationals starters.
"That lefty's better than everyone the past three months," Marlins manager Ozzie Guillen said of Detwiler in early September. "They don't talk about him."
Detwiler initially found success this season thanks to his power sinker, leaning almost exclusively on his fastball as he cruised through August. But lately, he's been mixing in more changeups and curveballs, most recently experimenting with the curve against the Braves on Friday.
After that outing in Atlanta, Washington manager Davey Johnson said Detwiler "showed me something" by pitching well and getting out of trouble in an important game against a playoff-bound team while dueling with a pitcher, Kris Medlen, who hasn't lost a start since 2010.
"That's all part of having experience up here and having some success and having some failure," Johnson said. "They're all trying to find out in their own mind what they think is going to work for them. That's part of the experience and becoming very confident in your own skin. Just a maturation process. It's not like just turning on a switch and it's there. You go through it."
If the Nats are going to get where they hope to be, Detwiler will have to come through in games much bigger than the one at Turner Field. So will Zimmermann, Gonzalez and Jackson.
You may not have heard their names as often as that of the ace forced to watch from the dugout, but odds are, you'll be seeing a lot more of the other guys soon.