Will good Peavy outlast bad Peavy?

At this point it seems obvious that when Jake Peavy faces the Seattle Mariners on Friday night, both of his identities will surface.

There is sure to be the impressive opening when memories of his dominating days in a San Diego Padres uniform will come to mind. Peavy’s outings since returning this season from surgery to reattach his latissimus dorsi muscle have all seem to show glimpses of his past form even if for just a short time.

On the other hand, there also figures to be a moment when Peavy hits a wall with stamina and his pitches no longer fly from his fingers with pinpoint accuracy. Earlier in the season that wall seemed to arise at around the 75-pitch mark until he started inching deeper into games. In his last outing, though, all he had in the tank was three innings of brilliance.

So what is a coaching staff to do when a pitcher is capable of losing his touch at a moment’s notice?

The White Sox could remove Peavy from the game at the first sign of trouble, but if that comes in the fourth inning like it did last weekend against the Texas Rangers it would but a heavy strain on the bullpen. Peavy ended up allowing a season-high seven runs in his last outing.

“We cannot predict to give him five innings,” manager Ozzie Guillen said. “We need him for more than five innings. The game will dictate what kind of move we got to make.”

Then there is the idea that if Peavy isn’t pushing himself to the limits with outings that come close to, or surpass, the 100-pitch mark, then he isn’t building the strength he needs to move forward.

It’s a tough call for a club that was counting on Peavy to turn into a front-of-the-rotation starter at some point this season.

“It’s a tricky point because one day he can pitch more than 80 pitches, and the next day he can go more he can go 100 plus,” Guillen said. “We’ll see how he comes out next time. We’re going to be aware. The game will dictate to us how we’re going to handle the situation, but we’ll wait and see.”

Peavy will head into the outing against the Mariners with a ho-hum 5-6 record and a 5.06 ERA. He is just 1-5 with a 5.63 ERA over his last nine starts since a relief appearance on June 25. But signs for hope include his tendency to pitch well on the West Coast, including in a pair of appearances at Seattle. He is 2-0 there with a combined 15 strikeouts and one walk.