The right-hander also agreed with White Sox general manager Ken Williams' assessment on Monday that the right elbow tendinitis that landed Contreras on the 15-day disabled list was nothing serious.
"I think Kenny is right on," said Contreras through an interpreter. "I'm feeling better, and today I felt good."
Contreras threw from distances of 45, 50 and 60 feet during his side session and mixed in some breaking balls to the pitch total. The plan is for Contreras to rest a couple of days and then throw again.
As for a Minor League rehab start being necessary before returning from the disabled list, a move made retroactive to July 14, Contreras left that decision in the team's hands.
"When the DL stint is up, I think I'll be ready," said Contreras, who could be eligible to pitch at the end of next week's series against the Twins at the Metrodome. "The last time I was on the DL, it was for my back and I didn't have to make a rehab start. I don't think it's necessary, but it's not my decision. It's Ozzie's and [pitching coach Don Cooper's] decision."
Scott Merkin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.