Wells is expected to be the first of the two back on the mound.
"I'd probably say two weeks," Wells said. "I don't know ... I've never been through something like this before.
"I know I'm not a very patient guy. If I'm feeling good, I'll try to push it. But one thing I'm not going to do is try to force something that isn't there yet."
Wells played catch with pitching coach Mark Riggins on Monday. He said he could still feel a little discomfort in the forearm.
"I feel it very mildly," Wells said.
Wells was asked about his throwing program.
"It will be real light throwing," he said. "It's going to be 60 feet and about 20 pitches to start with."
Wells injured his forearm on April 4 and went on the disabled list on April 8.
Cashner felt tightness in his right shoulder in the sixth inning of his first start on April 6. He also went on the DL on April 8.
Cashner's rehab is expected to be maybe two weeks longer than Wells', due to the fact the injury was in the shoulder and the Cubs want to be cautious with his arm.
Bruce Levine covers baseball for ESPNChicago.com and ESPN 1000.