But putting in some work on the bike is a positive sign for the right-hander.
"I think at this point, anything is encouraging," White Sox manager Robin Ventura said. "It's unique -- just something that you can't really do anything, can't really exert yourself at all. He's happy to actually be doing something, which is good."
Kelly Erickson is an associate reporter for MLB.com.
This story was not subject to the approval of Major League Baseball or its clubs.