ST. LOUIS -- Whenever he’s not in the starting lineup, Jacob Stallings makes an effort to catch a bullpen session hours before first pitch. So when Francisco Cervelli received most of the playing time in April, and again when Elias Díaz became the primary backstop in May, Stallings had plenty of time to work with Pittsburgh’s rotation between starts.

That time helps Stallings get to know pitchers, see what they’re working on and understand how they operate at their best. It’s also a time to build relationships, and two of them have led to more regular playing time for the Pirates’ backup catcher.

Stallings has essentially become the personal catcher for both Chris Archer and Joe Musgrove, two of the Pirates’ most important arms in the second half. Twelve of his last 13 starts have come with either Archer or Musgrove on the mound. Stallings, 29, has caught Archer’s past eight starts and each of Musgrove’s last four.

“It’s been good. Anytime you can get in a rhythm like that with anybody, it’s nice just because you’re so familiar with them,” Stallings said. “I think that type of thing is just as valuable as anything else, knowing what they do and how they like to get guys out. I like going out there and competing with those two guys. They’re fun to compete with and obviously such big competitors.”

Injuries have forced the Pirates to shuffle their personnel behind the plate over the past few years, but manager Clint Hurdle occasionally has shown a willingness to pair up certain pitchers and catchers. Veteran backup Chris Stewart, for example, caught the majority of Gerrit Cole’s outings during Cole’s excellent 2015 season.

Hurdle said he always tries to dig deeper into those relationships to understand what makes them work.

“As long as it’s not just about comfort. If there’s a conviction level tied to it and a commitment level tied to it, that’s when I have a buy-in and we’ll see where it goes,” Hurdle said. “I want to do what’s best for the team, but I want them also to tell me their ‘why.’ Not just, ‘Because I haven’t pitched well with the other guy’ or ‘I want to try something new, and I’ll put a rabbit’s foot in my pocket as well’ -- those types of things. That’s my feeling on it.”

So far, Hurdle has liked what he’s seen -- and the ‘why’ he’s heard -- from Archer and Musgrove with Stallings.

“It’s made sense. We wanted to see the value, see how it played out,” Hurdle said. “The results have been good.”

Polanco being re-evaluated
Rehabbing right fielder Gregory Polanco, currently with Triple-A Indianapolis on his way back from a bout of left shoulder inflammation, exited Sunday’s game after two plate appearances due to tightness in the shoulder.

Hurdle said Polanco saw a doctor on Monday, and the Pirates’ medical team was planning out his next steps. Polanco’s rehab assignment has not been shut down, as was the case for infielder Erik Gonzalez, but Polanco was off Monday for treatment and strengthening exercises.

Polanco was 6-for-25 with eight strikeouts over the first eight games of his rehab assignment, but he showed some clear signs of progress. He walked seven times in 32 plate appearances, and he recorded a homer and three doubles. That patience and power gave him an .886 OPS.

Brault on the mend
Left-hander Steven Brault, sidelined by a minor muscle strain in his left shoulder, played catch on Sunday for the first time since going on the injured list. Brault reported to the visitors’ clubhouse at Busch Stadium on Monday feeling good, maybe even better than expected, after his first throwing session.

“Everything felt really good,” Brault said. “We’re taking today off, then throwing again tomorrow and the next day. After that, I’m not exactly sure what the timetable is, but it shouldn’t be too long if everything feels good.”

Brault had been on a roll before exiting his July 5 start after four innings. In his past nine appearances dating back to May 18, the lefty owns a 2.44 ERA in 44 1/3 innings. Rookie right-hander Dario Agrazal assumed Brault’s spot in the rotation coming out of the All-Star break.

Around the horn
• The Pirates have talked with first baseman Josh Bell about taking a day off sometime soon, keeping in mind that he did not receive the same All-Star break as his teammates. While most players were resting and relaxing, Bell was slugging it out in the Home Run Derby and starting in the All-Star Game.

Bell started 92 of the Pirates’ first 93 games and ranked among the Major League leaders in plate appearances (400) and innings played (765 2/3) entering Monday’s action.

• Top prospect Mitch Keller was named the International League Pitcher of the Week on Monday, the second time he has received that honor this season. The right-hander worked six scoreless innings against Triple-A Columbus on Thursday, striking out eight while allowing only two hits and three walks.

• On Saturday, rookie reliever Luis Escobar became the 46th different player to appear in a game for the Pirates this season. Pittsburgh used only 48 players all of last season.