PITTSBURGH -- After undergoing season-ending shoulder surgery last September, Gregory Polanco returned earlier than anyone expected in late April. But that shoulder sent him back to the injured list on Saturday afternoon.

The Pirates placed Polanco on the 10-day IL, with the assignment made retroactive to Wednesday, due to posterior left shoulder inflammation. Pittsburgh recalled outfielder Jason Martin, the club’s No. 8 prospect, from Triple-A Indianapolis to replace Polanco on the active roster.

“It’s not a new injury. I think it’s just something with the activity, the games and the swings over time,” Pirates manager Clint Hurdle said. “We’ve talked about some things, and he’s shared some thoughts. We’ve talked publicly about the swing-and-miss and he feels there’s some restrictions in some of the shoulder mobility in trying to get to balls. This kid put everything he had into his rehab. He’s put everything he had into coming back. He played when we needed him the first two months of the season … trying to play through this and make it happen. I give him all the credit in the world.”

Polanco played catch under the supervision of an athletic trainer before Saturday’s 6-3 Pirates win over the Padres. He couldn’t predict how much time he will miss, but given the time he sat out earlier this season, he hopes it won’t be long.

“It’s bothering me in the back of the shoulder. It was a good idea to decide to go back and work, because obviously it wasn’t working right,” Polanco said. “I’m not helping the team the way I can do it. It was bothering me.”

Last September, Polanco had surgery on his dislocated left throwing shoulder to repair a torn labrum. He worked relentlessly through the rehabilitation process and met the Pirates’ most optimistic projection by making his season debut on April 22. He hit well for a few weeks, posting a .280/.344/.512 slash line with four homers in his first 21 games.

But Polanco has slumped since then, and June has been especially tough for the 27-year-old right fielder. Polanco was hitting .222 with 17 strikeouts in 40 plate appearances this month. He hasn’t played since last Sunday, and he had only started two games since June 12. Polanco admitted his shoulder was hampering his swing, which is at its best when its short and direct.

“It was affecting the swing,” Polanco said. “It was getting long, and I was getting under the ball every time.”

Polanco was the Bucs’ most productive hitter last season, posting an .839 OPS with 23 homers and 81 RBIs, but they are built to withstand his absence. Left fielder Corey Dickerson is back in the lineup and playing well after recovering from a shoulder injury of his own, and rookie Bryan Reynolds’ early success has made it impossible to take him out of the lineup.

The Pirates briefly balanced a five-man outfield rotation with those three alongside center fielder Starling Marte and veteran Melky Cabrera. It figures to be a four-man mix while Polanco is sidelined, with Martin adding depth off the bench.

Martin, 23, made his Major League debut on April 6 while the Pirates were saddled with injured outfielders. He hit .229 with a .575 OPS, two doubles and two steals in 17 games for Pittsburgh. He hit .230 with a .679 OPS in 45 games after returning to Triple-A.

“It’s been challenging. He went down and tried to find his way offensively,” Hurdle said. “He continues to work defensively, to run the bases aggressively. The offensive numbers are not what he wants right now, but he’s got an entire half of a season to work and continue to get better and improve.”

Pitch, Hit and Run winners

On Saturday morning, the Pirates hosted the annual Pitch, Hit and Run skills competition. The top 12 baseball and top 12 softball qualifiers from Pennsylvania, West Virginia and Ohio battled it out at PNC Park for spots in the national finals to be held during this year’s All-Star Game festivities in Cleveland.

The following participants were named champions: Katie Rohrbaugh from Petersburgh, W.Va. (7- and 8-year-old softball division), Nick Arotin from Ebensburg, Pa. (7- and 8-year-old baseball division), Adyson Copley from South Point, Ohio (9- and 10-year-old softball division), Parker Shutty from North Cambria, Pa. (9- and 10-year-old baseball division), Kassidy Watson from Petersburg, Pa. (11- and 12-year-old softball division), Caden Arbaugh from Seneca Rocks, W.Va. (11- and 12-year-old baseball division), Ava McClean from Vanderbilt, Pa. (13- and 14-year-old softball division), and Landon Urcho from Bentleyville, Pa. (13- and 14-year-old baseball division).