PHILADELPHIA -- Zach Eflin is the latest Phillies starter to be moved to the bullpen.

Phillies manager Gabe Kapler said Tuesday afternoon at Citizens Bank Park that Eflin has been bumped from the rotation to make room for left-hander Jason Vargas, whom they acquired Monday in a trade with the Mets. Vargas is scheduled to start Friday against the White Sox. He is 6-5 with a 4.01 ERA, including a 3.34 ERA in 12 starts since May 25. Eflin, meanwhile, has a 10.64 ERA in his past six starts.

“If I don’t like it, I should pitch better,” Eflin said. “I hadn’t really been doing my job. Going to the bullpen is another opportunity for me. It’s a challenge. I’m a fan of challenges. Go down there and be the best version of myself I can be.

“I still believe wholeheartedly that I’m a starter.”

The Phillies entered the season with Eflin, Vince Velasquez and Nick Pivetta in the rotation. Each has been moved to the bullpen at different points this season. Velasquez returned to the rotation on June 16. Pivetta joined the bullpen less than two weeks ago.

Kapler said Eflin could be ready to pitch behind Velasquez and Jake Arrieta, each of whom has had difficulty pitching deep into games: Velasquez because he racks up a high pitch count and Arrieta because he is pitching with a bone spur in his right elbow.

“One of the things that we’re potentially excited about is seeing Eflin in a role where he could take down several righties in a row, and utilize his good fastball-slider combination, among his other offerings, to be effective out of the 'pen,” Kapler said. “I don’t think we have to make any long-term declarations on this front, just take this first step of having him available tonight and potentially the next two days.”

Vargas will not officially join the team until Thursday. Kapler made a point to mention the background work the team performed on Vargas, who physically threatened a Mets reporter on June 23. Kapler said he talked to at least 10 people that know Vargas and that “praise was pretty effusive.”

“I think he gives us depth,” Kapler said. “I think he gives us stability, and a guy who has been extremely competitive over a really long period of time. The other thing that stands out is that we’ve done a lot of homework on the character and the make-up, understanding that whoever we bring into this room, we would like them to be able to make an impact outside the lines. Really, really outstanding teammate reports on Jason about his competitiveness, about how much he cares, about how professional he is and about what he brings to a clubhouse and his teammates.”