Pestano posted a 1.42 ERA in six appearances since rejoining the club on June 20, striking out nine and walking none. However, he took the loss in Wednesday's 14-frame marathon, after giving up a home run to left-handed-hitting Jacoby Ellsbury in the final inning.
"I think Vinnie was really doing a good job against right-handers," Indians manager Terry Francona said. "We knew coming in that's what we liked him to face. We tried to find places for him to face righties. That's not always the easiest -- and when you have a normal bullpen, it can be a little challenging. That doesn't mean he's not going to be back."
Lefties are 7-for-13 (.538) with three extra-base hits when facing Pestano this season, while righties are just 6-for-26 (.231) when facing the 29-year-old. Pestano's career splits show the same trend, as his slash line against right-handed hitters is .166/.255/.273, compared to .277/.358/.471 against lefties.
Since compiling a 2.57 ERA across 70 games with Cleveland in 2012, Pestano has struggled to find consistency at the big league level. He made this year's Opening Day roster, but quickly found himself back in the Minors on April 9 -- after surrendering six runs in 2 2/3 innings.
"Trying to gauge where Vinnie is, it's not the easiest thing -- and it's hard for Vinnie, too," Francona said. "When you're in a reduced role, it can be difficult for the player."
McAllister (3-5, 5.63 ERA) took a tough-luck loss on Saturday, but still held the White Sox to three runs over seven innings in his first Major-League start since May 21.
"I was extremely happy with it," McAllister said. "It's kind of what I had in mind and was hoping I was able to accomplish. Obviously, it would've been a lot better if we were able to get the 'W.' We didn't today, but again, it's a good step in the right direction."
The right-hander spent almost four weeks on the disabled list with back soreness and was optioned to Columbus shortly after being activated on June 18. He went 5-0 with a 2.66 ERA across seven Minor League outings, recording 38 strikeouts versus eight walks in 40 2/3 innings.