Jordan Zimmermann pitched six strong innings in what was likely his final start of 2015. The right-hander is expected to test the free agency waters in the offseason. (Jason Getz/USA Today Sports)

The likely final pitch in Jordan Zimmermann’s distinguished Washington Nationals career was an 87-mph first-pitch slider twirled over the plate to Andrelton Simmons, who grounded out to end the sixth inning in Wednesday’s 2-0 loss to the Atlanta Braves. The season ends in four days, and free agency awaits the Nationals right-hander, who is not expected to return.

Saying goodbye is difficult, especially when Washington is the only team Zimmermann has played for and his list of accomplishments is so long. Zimmermann will leave as the Nationals’ all-time leader in wins (70), starts (178), innings pitched (1,094), strikeouts (903) and fierce stares from the mound (every five days). The Nationals are expected to turn to their crop of young pitchers, meaning the 29-year-old, perhaps the best starter in the team’s 11-season history, likely will be in a different uniform next season.

“I’ve been thinking about it the last couple days, actually,” said Zimmermann, offering a rare glimpse of sentimentality. “I may not be around these guys anymore next year. Some of these guys have been around seven years and had a great time. We’ll see what the offseason brings.”

Plucked out of the University of Wisconsin at Stevens Point in 2007, Zimmermann reached the majors in 2009 and overcame Tommy John surgery. Since then, he became a model of consistency, durability and comportment on the mound. He has made at least 32 starts and tossed at least 195 innings each of the past four seasons.

“He’s like an artist, man,” said fellow starter Gio Gonzalez, who has shared a rotation with Zimmermann since 2012. “A remarkable pitcher. He’s just a bulldog, a workhorse, a top-of-the-rotation son of a gun.”

No matter where he ends up next season, Zimmermann will be remembered for his role in some of the most important and exciting moments in Nationals history. Asked to list his favorite moments during his career, Zimmermann pointed to his no-hitter on the final day of the 2014 regular season as the best, followed by reaching the playoffs for the first time in 2012 and his electric relief outing during Game 4 of the NLDS that year.

“When I first got drafted, we were at the bottom,” Zimmermann said. “We had a few good drafts and got some great talent and rose to the top and made the playoffs a few times. I’ve enjoyed every day.”

Teammates have admired Zimmermann for his ability and no-nonsense personality. He did his work diligently and never sought attention.

“He’s kind of chosen to take that route,” said shortstop Ian Desmond, who debuted in 2009 along with Zimmermann. “I’m sure there’s certain opportunities where he could have gotten in front of a camera and did a commercial. But that’s not about him. He’s about going out there and handling his business and pitching. That’s what he wants to do and he thrives. Whether he gets recognition or not is not going to change him.”

Against the Braves on Wednesday, Zimmermann gave up single runs in the first two innings and not much else on 82 pitches. He crossed the 200-inning threshold for the second time — only the second starter to do so in Nationals history. The Nationals’ offense sputtered, mustering six hits and three walks. Washington went 1 for 9 with runners in scoring position, the lone hit coming from Zimmermann’s fifth-inning single.

“It’s pretty hard,” catcher Wilson Ramos said of Zimmermann’s likely departure. “I want that guy on this team. . . . This is the business. You can be here one year and you can’t the next year.”

Zimmermann finishes his Nationals tenure with a 70-50 record and a 3.32 ERA. Despite pitching 201 2/3 innings, this qualifies as a down year for Zimmermann at 13-10 and a 3.66 ERA. He nonetheless will enter free agency as one of the market’s most sought-after starters.

“Every team’s going to have a shot,” he said. “We’ll see this offseason what happens and if [the Nationals] come calling.”

Added Desmond: “And any team, whether it’s the Nationals or anybody else, will be lucky to have him.”

The reality is sad for fans and teammates. The Nationals potentially will need spots for Tanner Roark and Joe Ross in next season’s rotation and have one of the best prospects in baseball, Lucas Giolito, nearing the majors. So when Zimmermann notched the final out of the sixth inning and walked into the dugout, everyone knew the significance of the situation.

Desmond, also another pending free agent, embraced Zimmermann with a big hug. This was goodbye.

“I made some great friends along the way,” Zimmermann said. “I’m going to miss these guys.”