PITTSBURGH -- In Friday’s shutout of the Cardinals, the Pirates showed through three relief choices how they could shape their bullpen down the stretch.

With former closer Richard Rodríguez and leverage option Clay Holmes traded to the Braves and the Yankees, respectively, ahead of the Deadline, manager Derek Shelton will be working with an altered mix in tight games.

What things is the skipper prioritizing when he sends relievers into these situations? Here’s how it played out Friday.

1) Underwood under development
Duane Underwood Jr. leads the Majors in relief innings pitched after going for 1 1/3 against the Cardinals, boosting his total to 66 2/3 innings over 39 appearances. However, only three of those outings have come with the Pirates leading by one to three runs -- effectively, in a save or hold situation.

The month of July was not kind to Underwood, who allowed 12 runs (11 earned) in 10 2/3 innings around a bout of right side discomfort that sent him to the 10-day injured list. However, something in July also pointed toward steps being taken.

Underwood pitched on July 21, then got four days of rest before his next outing on July 25. But that wasn’t really rest: It was a period of enhanced refinements that Shelton said has led to the right-hander’s success in August (0.79 ERA).

“That’s the one hard thing when you make adjustments during the season: Sometimes, that adjustment doesn’t let you pitch in a game that night and you have to wait an extra night,” Shelton said. “I think in terms of development, it was important for us to get Duane in a better spot, and he embraced it and worked really hard on it.”

An improved delivery is one thing Shelton, pitching coach Oscar Marin and bullpen coach Justin Meccage keyed in on, but the manager mentioned that Underwood’s pitch mix has undergone some refinement recently. Jumping off the page is a sharp rise in four-seam fastball employment: It’s up to a 44.4% usage in August, the only month it’s been above 38%. Commanding it well has allowed his curveball to play up (season-high 42.1% whiff rate in August), and if that trend continues, he could be used more and more in high-leverage situations.

2) Bednar beyond closer
Yes, David Bednar has made his case as the best closing option on the Pirates. He leads the team’s relievers (minimum 10 innings pitched) in ERA (2.54), WHIP (1.027), FIP (3.05) and strikeout-to-walk ratio (3.81). Not to mention he leads all Bucs pitchers in bWAR (1.4).

However, that overall success has also bled into success in many different situations -- one-inning vs. multi-inning relief appearances, inherited-runner scenarios vs. the heart of the order. So with two runners on and two out in the seventh inning of Friday’s game, Bednar relieved Underwood to face power threat Tyler O’Neill, and he got him to fly out.

Bednar cruised through the back portion of the Cardinals’ lineup in the eighth, allowing one soft single to Paul DeJong, but preserving the shutout. Expect Bednar to be used as the go-to reliever in the biggest moment in a game vs. the traditional ninth-inning guy.

“I think that is as valuable as anything, because sometimes the highest leverage situation in a game is not the ninth inning,” Shelton said. “It’s coming in and getting guys out, and David’s done a really nice job in those situations.”

3) Stratton stabilizes back end
Veteran Chris Stratton isn’t a stranger to protecting leads this season, but he’s typically done it earlier in the game vs. the eighth or ninth inning. Seven of his 42 appearances before the Deadline began in the eighth or ninth inning, but now, four of his past seven have been in those innings.

That’s not because Stratton is the new closer. It’s largely a product of -- on top of his general consistency -- his veteran status.

“Our bullpen has gotten very young, very inexperienced and having some stability and that mentality at the end of the game -- whether it’s the seventh, eighth or the ninth -- is important,” Shelton said.

Shelton referenced Rodríguez with the Braves as an indication of how the Pirates have to approach their bullpen with guys like Stratton, who is ahead of the curve in terms of experience. In Pittsburgh this season, Rodríguez was the guy in save situations, as he had a ton of experience in late setup roles and was dominant for much of the year.

However, the Braves have a few guys who can take the ninth, and in turn, Rodríguez has pitched as many games in the seventh or earlier as he has in the eighth or later. Stratton will likely be featured more in the latter for the Pirates now, though his versatility helps.

“Sometimes, when you’re a club like we are, the necessity is to pitch more at the back end,” Shelton said. “... The ability to have guys that can pitch in those ways and go multiple innings and pitch in higher-leverage roles is going to be really important for us moving forward.”