Bronson Arroyo dresses next to Lucas Giolito in the Washington Nationals’ clubhouse at spring training. Both pitchers are tall right-handers, but that is where the similarities end. Giolito was born in 1994, in the summer before Arroyo’s senior year in high school. He has not yet pitched in the major leagues. Arroyo has logged 15 seasons.

When the Nationals’ veterans assigned Giolito a research project this spring, he interviewed Arroyo as a source. The topic: Dusty Baker, the Nationals’ manager. Arroyo played six seasons under Baker with the Cincinnati Reds.

“I’m happy I’m sitting next to him,” Giolito said.

The Nationals are happy to have Arroyo, too, although he must prove he can still contribute on the field. He has not pitched since June 2014, before Tommy John surgery and after a stretch of more than 2,000 innings across 10 seasons, dating to the celebrated Boston Red Sox of 2004.

David Ortiz, 40, is embarking on a final season farewell across the state in Fort Myers. Arroyo, 39, is the only other active member of the 2004 Red Sox. He hopes to stay longer in the majors.

“I’ve been saying for a long time, I’m going to outlast Papi,” Arroyo said. “But I’ve got to make it through this season. He might outlast me if I don’t make this club, or if my arm can’t handle the torque of pitching multiple innings.

“But I’m proud of what I’ve done in this game, man. If I don’t make it out of this camp and this arm just won’t go, I’m completely satisfied with what I’ve done in the game.”

When Arroyo was a minor leaguer with the Pittsburgh Pirates, in the late 1990s, he put a monetary figure on his dreams: $20 million. That seemed reasonable, considering the going rate for pitching at the time, and Arroyo eclipsed it long ago. To date, he has earned more than $95 million.

The last chunk of that — a $9.5 million salary last season and a $4.5 million buyout for a 2016 option — bounced from the Arizona Diamondbacks to the Atlanta Braves to the Los Angeles Dodgers last season, all while Arroyo recovered from surgery.

The first trade came on June 20. Arroyo was summoned to the manager’s office during a game in Phoenix to meet with Dave Stewart, the Diamondbacks’ general manager. Stewart told him he had been traded to the Braves.

“Why would they want me?” Arroyo said he asked. The answer was: They really didn’t. The Braves had agreed to take Arroyo’s salary in order to get a top pitching prospect, Touki Toussaint, in exchange for a utility infielder.

Arroyo dutifully reported to the Braves’ complex near Orlando, back in his home state. He golfed with friends and visited his parents and worked on his elbow rehabilitation among the Braves’ rookie league players. This continued until July 30.

“I’m showering up one day, I’m just about to leave, and one of the young kids comes up to me and goes, ‘Hey, man, I think you just got traded to the Dodgers,’ ” Arroyo said. “And I go, ‘What?’ He goes, ‘Yeah, I just saw it on Twitter.’ So I get in the car, I call John Hart: ‘Did you just trade me to the Dodgers?’ He says: ‘Yeah, I did. It’s all monetary components. I had to do what I had to do.’”

Hart, the Braves’ president of baseball operations, had teamed with the Dodgers and the Miami Marlins on a zany transaction involving 13 players, a draft pick and lots of shifting dollars. Arroyo, who still had his rental home in Arizona, moved back in and continued his recovery at the Dodgers’ complex in Glendale.

Arroyo took no mementos from the Braves. He got an equipment bag from the Dodgers, but gave it to his offseason catch partner. The checks kept coming, of course, but, otherwise, Arroyo had nothing tangible to show for his employment by those teams — just some lines in the transaction history on his baseball-reference page.

“Nothing,” he said. “If I would have put on a uniform and stood in their dugout, I’d claim those teams. But I can’t claim them when I didn’t even put the uni on once.”

Arroyo never did appear in a game last season, even in the minors. He has pitched only in the majors since 2003, when the Red Sox claimed him off waivers and eventually put him on their American League Championship Series roster. A 2006 trade to the Reds for Wily Mo Pena, an underachieving slugger, began an eight-year run in which Arroyo never missed a start.

He won his last three starts with the Diamondbacks in 2014, despite intense pain in his elbow. He said he could not straighten his arm, and teammates would laugh at his bullpen sessions. His fastball was diminished, but Arroyo has never thrown hard and continued to trick hitters. He still had command, so he doubted he had torn his ulna collateral ligament.

“I had always found a way out of that rabbit hole,” Arroyo said, but tests revealed the worst. Finally, he hopes, he is ready for a comeback.

“Bronson knows how to pitch, and he knows how to lead,” Baker said. “He knows when to say something and when to be quiet. I don’t know where he’s going to fit on this club, but I’m hoping that he’s well enough to fit somewhere. He can add something.”

Arroyo could have returned to Cincinnati, with a much better chance to make the team. The Nationals have Max Scherzer, Stephen Strasburg and Gio Gonzalez at the front of their rotation. Joe Ross and Tanner Roark are solid options for the back end, with Giolito looming in midseason.

But the Nationals made a stronger offer than the Reds, and Baker was a draw.

“If I go out in spring training and I’m throwing 84, 85, and I’m getting my butt kicked a little bit, I need someone who can look between the lines and say: ‘Yeah, but you know what? He’s good enough and I know what we’re going to get for the season,’” Arroyo said, “versus somebody who’s never seen me throw before and be like, ‘Oh, man, this guy’s washed up.’ ”

The exhibition season, which starts this week, will say a lot. Arroyo has no desire to pitch in the minors, but if the Nationals cut him, he may return home, stay in shape and wait for another chance. If nothing comes — and Ortiz outlasts him as the final active member of the 2004 Red Sox — Arroyo is fulfilled.

“If you rewind to my 18-year-old self and you map out my career, without question, I’d be totally content with that,” he said. “It would have exceeded anything I would have thought.”