ST. LOUIS -- The Pirates have shut down right fielder Gregory Polanco’s rehab assignment due to recurrent soreness in his left shoulder, director of sports medicine Todd Tomczyk said on Wednesday, creating further uncertainty as to when Polanco might rejoin Pittsburgh this season.

Polanco exited Sunday’s game with Triple-A Indianapolis after two plate appearance due to tightness in his left shoulder. According to Tomczyk, Polanco had not reported any more shoulder soreness than usual before that game, but Polanco noted that he felt uncomfortable trying to reach an outside pitch during his second plate appearance.

Polanco will be re-examined in Pittsburgh.

“The shoulder is strong. The shoulder is stable, based on our medical team and doctor in Indianapolis,” Tomczyk said. “We just need to figure out, a little bit more granular, the details of what’s causing the soreness and the discomfort in the back of his shoulder.”

Polanco’s current soreness is related to the surgery he underwent after dislocating his shoulder on an awkward slide last September, Tomczyk said, but doctors are trying to determine whether it’s being caused by a muscular issue or simply scar tissue from the operation.

Polanco beat even the most optimistic projections by returning to the Bucs lineup on April 22 and hit well during his first few weeks back in the Majors. But Polanco’s tight shoulder began to affect his swing, and he was ultimately placed on the 10-day injured list on June 22 due to left shoulder inflammation.

The Pirates are not currently in need of another outfielder, which should allow them to be patient with Polanco. They are already balancing four outfielders -- Starling Marte, Corey Dickerson, Bryan Reynolds and Melky Cabrera -- in three spots.

But Polanco’s extended absence could affect the club's thinking as the July 31 Trade Deadline approaches, as Dickerson and Cabrera -- both impending free agents -- seemed like potential trade chips whether the Pirates were in or out of the postseason race. If Polanco remains sidelined for a significant period of time, the Bucs may not have the same luxury of outfield depth.

Trainer’s room

• Infielder Erik Gonzalez, whose rehab assignment was stopped due to a left hamstring strain, passed a battery of tests over the past few days and rejoined the Triple-A club on Wednesday. He is beginning a new rehab assignment, which means he can spend up to 20 more days with Indianapolis.

• Reliever Keone Kela (right shoulder inflammation) felt strong and reported no issues after his first two rehab outings with Indianapolis, Tomczyk said. Kela is scheduled to pitch again in Triple-A on Thursday.

• The Pirates are still determining what comes next for Francisco Cervelli after he was seen by Dr. Michael “Micky” Collins, an expert in dealing with sports-related concussions. Cervelli is working out and practicing with the team, but he has not been cleared to play in games or catch.

• Opening Day starter Jameson Taillon (right elbow flexor tendon strain) threw five pitches off the slope of the mound Wednesday in addition to his flat-ground work. The Pirates are assessing how Taillon responded to that session, but they expect he will resume his throwing program this weekend.

• Left-hander Steven Brault (left shoulder strain) is scheduled to throw a bullpen session this weekend, an encouraging report after he was placed on the injured list on July 6.

• Right-handers Chad Kuhl and Edgar Santana, both out for the year following Tommy John surgery, both threw off the mound for the first time earlier this week.

• Right-hander Rookie Davis (forearm) is scheduled to throw a bullpen session this weekend in Bradenton, Fla. Davis has been out since June 8.

• Pitching prospect JT Brubaker (right forearm strain) is rehabbing in Bradenton but not throwing. The right-hander has not pitched since a rehab outing on June 23.

• Outfielder Lonnie Chisenhall, who has not played for the Pirates this season, was diagnosed with “chronic bilateral calf strains,” Tomczyk said. Doctors recommended continued rest and rehabilitation.

Around the horn

• First baseman Josh Bell was out of the lineup on Wednesday for just the second time this season. The Pirates had been planning on giving Bell a day off, bundled with Thursday’s scheduled off-day, to compensate for his lack of a true All-Star “break.” Jose Osuna started at first base, batting cleanup.

• The Pirates’ 3-1 win over the Cardinals on Tuesday night was Clint Hurdle’s 711th as Pittsburgh’s manager, tying him with Chuck Tanner for fourth-most in franchise history. Only three Pirates managers have been at the helm for more victories: Fred Clarke (1,422), Danny Murtaugh (1,115) and Jim Leyland (851).

• The Pirates and Pirates Charities on Thursday will present the opening night of “Heading Home, the Tale of Team Israel,” a documentary by Seth Kramer, Daniel A. Miller and Jeremy Newberger, at Regent Square Theatre in Edgewood. There will be a free screening of the film as well as a question-and-answer session with MLB.com’s Jonathan Mayo, Pirates broadcaster Greg Brown and team president Frank Coonelly. Pitcher Joe Musgrove is also scheduled to make an appearance during a street fair that runs from 5-7 p.m. in Frick Park on South Braddock Avenue.