"That's what Jose's problem [has been] in the past," Guillen said. "When he doesn't throw the split-fingered forkball for a strike, he runs into trouble. The velocity is there. I don't think Jose has the confidence right now letting the ball go. That's what I see. Maybe I'm wrong, but every time he lets the ball go, the ball tails somewhere."
So Contreras' upcoming side session, in preparation for his next assignment, on Sunday at home against the Blue Jays, will focus on command issues. He used the split-finger pitch only 12 times Tuesday night, throwing it twice for strikes, Cooper said.
"When he's throwing good, there's somewhere between 20 and 35 of those in there," Cooper added. "Obviously that's going to be the focus of our next sideline. ... That's a major weapon for both lefties and righties for him, but it's also command of the fastball, the ability to get all his pitches over [and] the ability to constantly get ahead of lefties."
Left-handed hitters have proven a challenge for Contreras this season. They are hitting .342 against him, as opposed to .200 for right-handed hitters. Contreras has walked 10 left-handed hitters and only one right-hander.
If it sounds like Contreras is being remade in-season, it's with good reason. Guillen said he doesn't see a better option right now to replace the veteran right-hander in the rotation.
"With Jose, people have to understand and be patient about it," the manager said. "We're lucky to have Jose on the mound. Plan B? I don't see it happening that quick."
Cooper is confident that health is not an issue. Contreras' 2008 season ended after 20 starts when he ruptured his left Achilles tendon.
"It's crossed my mind: 'Is he able to drive off there and ride off there?' But when I see the down-angle pitches being good ... when I see him run better to first base than I've ever seen him run, that's not the case. It crossed my mind, but the bottom line is he's healthy," Cooper said.
Repairing Contreras' confidence might be just as important as any mechanical tweaks. Contreras has said he won't consider the comeback from the Achilles problem complete until he wins a start.
"He's always been a guy that's been very convicted and worked hard," Cooper said. "He wants to get back out there. He's frustrated. He wants to do well. He's a very proud guy. We've known that for a while."