Sam Coonrod said his new slider was very good and very sharp after he started throwing it last month with a split-finger grip. But the pitch also proved to be very painful.

The slider, Coonrod said, caused discomfort in his elbow and put him on the injured list last month after he threw it in just two games. Coonrod tried throwing it again Wednesday during a rehab assignment at triple A before his elbow flared up again.

The Phillies, manager Joe Girardi said, are shutting down the reliever for three days before he resumes his rehab schedule. When he does, Coonrod will be throwing his slider with a standard grip. And he thinks he can make a quick return to the Phillies.

“It’s a really sharp slider,” Coonrod said Friday. “It’s unfortunate that I can’t throw it right now, but I’ll be fine not throwing it.”

Coonrod said the pitch -- which he thinks was invented by Trevor Bauer -- was suggested to him by Phillies pitching coach Caleb Cotham.

“‘Wow, that’s a good pitch,’” Coonrod said he thought of the slider when he first tried it. “Of course, I can’t use it.”

He threw it 15 times in his final two appearances before being placed on the injured list on June 25. The injury will cost him more than a month. Elbow injuries, especially for pitchers who throw triple-digit fastballs, can often be tough to overcome. But Coonrod is confident that shelving the new slider is the cure he needs.

“We’ve done everything we needed to do. Looked at it. Scanned it. Did everything. It’s fine,” he said. “For whatever reason, whenever I throw that type of supination motion with a split grip it bothers my elbow. Once I stopped that, they gave me some medication, and I think I’ll be fine.”

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Coonrod had a 4.18 ERA in 27 appearances with the Phillies, but his ERA inflated by nearly a run when he allowed three runs in two-thirds of an inning in his final outing before moving to the injured list. He started the season with just four earned runs in his first 21 innings over 19 appearances. The average speed of his four-seam fastball (98.7 mph) is the fifth-fastest among all pitchers.

The Phillies are trying to add relief help before next Friday’s trade deadline, and the hard-throwing Coonrod, if healthy, would be an addition to a thin bullpen. First, he has to throw his old slider.

“With all the torque and force, I guess my arm just can’t handle it right now,” Coonrod said. “That pitch. Everything else is fine. It’s just that unique slider causes big problems.”

» READ MORE: Zach Eflin’s injury reminds Phillies how important it is to add pitching before the July 30 trade deadline

Bohm’s back

Alec Bohm returned to the Phillies on Friday, nearly two weeks after testing positive for COVID-19. Bohm rehabbed in triple A for just one game before being activated.

“We felt like he felt all right and to get him back here,” Girardi said. “There’s guys who don’t necessarily need a lot of time in rehabs. He’s been working with us the last three or four days and he never really got really sick, so we felt good about him.”

Relievers Bailey Falter and J.D. Hammer remain on the COVID-19 injured list and Girardi said both pitchers will be out through the weekend.

Extra bases

The Phillies have not yet decided on who will start Monday in place of Zach Eflin, who cannot return from the injured list until Tuesday at the earliest. Spencer Howard and Chase Anderson are the likely options. ... Vi nce Velasquez will start Saturday night against Atlanta left-hander Drew Smyly.