SAN DIEGO -- Cal Quantrill had a bullpen session scheduled for Sunday at Petco Park. The Padres asked their rookie right-hander to hold off until after their game against the Cardinals.

Quantrill, after all, has been used in all sorts of roles this season. The team's No. 10 prospect, according to MLB Pipeline, has served as a starter, and he's pitched in both short and long relief. With right-hander Trey Wingenter battling illness, it seemed possible Quantrill's number might get called.

Sure enough, in a tie game in the 10th inning, Quantrill was summoned to face the heart of the St. Louis lineup. He retired Jose Martinez, Paul DeJong and Paul Goldschmidt in order.

"To a certain extent, pitching's pitching," Quantrill said of his role this season. "The goal is still to get three outs before they cross home plate."

That will still the goal on Wednesday when Quantrill is slated to start against San Francisco. After spending 2 1/2 weeks in the 'pen for the first time in his career, Quantrill is back in the rotation.

The Padres have essentially decided to use Quantrill as a back-and-forth pitching piece. This year, the team is giving its starters five days' rest between outings, meaning a six-man rotation is necessary when the schedule is light on off-days.

In those cases, it's Quantrill who shifts into the starting mix. That’s not an easy role, but the Padres have been thoroughly impressed with the way Quantrill has handled it.

"You never know until you let him do it, and he never did it in his Minor League career," manager Andy Green said. "Until that opportunity, you wait and see how they respond. But ... for us to be really good, our best pitchers need to be here, whether they're in the rotation or in the bullpen. He's definitely in our best 13."

That's a simple concept on paper. But Quantrill has been a starting pitcher his entire life. He's been tasked with adjusting on the fly at the sport's highest level.

Then again, the Padres haven’t been indiscriminate with their use of Quantrill. When they know he's starting in five days, that's the last time they'll use him in the 'pen for any length. (He threw two innings on Friday against St. Louis.)

After that, they'll only use Quantrill for one inning on his scheduled bullpen day -- though they'd prefer to avoid doing so if possible.

Not that Quantrill minds.

"I'd rather pitch in the game," Quantrill said. "When I'm doing my bullpens right, they're pretty close to game speed anyway."

"I was excited to pitch yesterday," he added. "Routine is wonderful if you can maintain it. But you don't want to ever become a victim of your routine.”

'You're messing with all five of us'

The Padres' rotation held a meeting Friday night at the beginning of the homestand. For the pitchers who weren’t starting, it was time to shake up the pregame routine.

Collectively, the group decided that the rest of the rotation would join that day’s starter for his pregame bullpen session. Then, they would walk to the dugout together, prior to first pitch.

"You're messing with all five of us," said right-hander Chris Paddack.

"The vibe's cool," added lefty Joey Lucchesi. "It showed that we have each other's back."

The rules: Don't talk while the starter is warming. After he's done, say whatever needs to be said to get him fired up.

Other topics were discussed during the rotation's meeting. Most notably: a need to press the reset button at the midway point. After a fast start to the season, the Padres' starters struggled in June.

One way to turn things around, they said, was to make an already close-knit group even closer.

"We wanted to show moral support for each other in any way we could," Matt Strahm said. "We've got five starters on five different routines. We kind of get away from each other, and we stick to our own routine. But we made an emphasis: Get here, get your work done, but be ready to go out with that starter. Show 'em that support."

Worth noting

• Right-hander Dinelson Lamet threw a bullpen session at Petco Park on Monday. After missing a season and a half after Tommy John surgery, it's possible Lamet returns this weekend in Los Angeles, though Green wouldn't commit to it. The 26-year-old right-hander threw 85 pitches on Friday for Triple-A El Paso in his sixth rehab outing. He could be lined up to start on Thursday.

• Catcher Francisco Mejia, who sustained a bruised right forearm after he was hit by a pitch on Saturday, returned to the lineup on Monday night.

• Left fielder Hunter Renfroe was out of the lineup for all three games against the Cardinals this weekend as he battled the flu. But he pinch-hit on Sunday, and he started Monday night, batting in the cleanup spot.