PHOENIX — Tony Sipp walked up behind Patrick Corbin on Friday afternoon, patted his now-former teammate on the back and began his round of goodbyes in the visitors’ clubhouse at Chase Field.

“Hey, man,” Sipp said to get Corbin’s attention. “I’m out.”

Corbin, seated at his locker, asked Sipp what he was talking about. Sipp repeated the same two words. The Washington Nationals had just designated the 36-year-old Sipp for assignment, meaning the reliever’s future with the team is uncertain. Sipp will go on waivers and could be picked up by another club. If he isn’t, after a 10-day period, he is likely to become a free agent.

Sipp signed in February to be the Nationals’ left-handed specialist, had up-and-down results this season and wound up the third player DFA’d this week, along with Javy Guerra and Michael Blazek, to make room for Daniel Hudson, Hunter Strickland and Roenis Elías, the relievers Washington acquired at the trade deadline.

The Nationals are excited to roll out their new-look bullpen, starting with a Friday night matchup with the Arizona Diamondbacks here, but Sipp represented the other side of midseason roster building. Every addition triggers a subtraction. That’s the business. That’s why, by 3:30 p.m. Friday, Sipp had changed out of his uniform and into a T-shirt and jeans. And a lot of hugs followed.

“One of the toughest things of my job is DFA’ing guys like that, and especially a guy like Tony Sipp, and Javy and even Blazek, for the short time I’ve known him,” Manager Dave Martinez said. “You build relationships with these guys, and the toughest thing to do is call them in here and tell them we’re going in a different direction. And I wish those guys all the best.

“It was just a decision that we had to make. We picked up a lefty that is going to help us in the back of the bullpen, so that’s the only reason why we [designated Sipp for assignment].”

That lefty is the 31-year-old Elias, who comes to the Nationals from the Seattle Mariners. When he was acquired Wednesday, it seemed logical that either Sipp or Matt Grace would be DFA’d to clear space on the 25-man roster. Washington doesn’t need to carry four left-handed relievers in an eight-man bullpen, and now has three in Elias, Grace and closer Sean Doolittle. Sipp was used in more matchup situations than Grace, who has mostly been a multi-inning reliever since a short run as a specialist in June. Sipp had a 4.71 ERA in 36 appearances and lefties had a .666 on-base-plus-slugging percentage against him. Grace has a 5.91 ERA in 45 appearances and lefties have a .659 OPS against him.

Their numbers are comparable. But since they handled different roles, with Grace providing long relief, Sipp was the logical swap out for Elias. Guerra and Blazek had taken multi-inning, mop-up appearances in recent weeks. Now Grace makes the most sense in those spots.

“I talked to Matt as well today, and told him that he has to be readily available to pitch multiple innings,” Martinez said. “He gets it, and he wants to help us any way he can.”

LINEUPS

Nationals (57-51)

Trea Turner, SS

Adam Eaton, RF

Anthony Rendon, 3B

Juan Soto, LF

Howie Kendrick, 1B

Brian Dozier, 2B

Yan Gomes, C

Victor Robles, CF

Joe Ross, P

Diamondbacks (54-55)

Jarred Dyson, CF

Ketel Marte, 2B

Eduardo Escobar, 3B

David Peralta, LF

Adam Jones, RF

Jake Lamb, 1B

Nick Ahmed, SS

Carson Kelly, C

Alex Young, P