Colon, who is currently with Triple-A Pawtucket, fired five masterful innings in his April 3 start, but his oblique became tender either during or in the days following that outing.
The big righty was examined by Boston's medical staff on Wednesday.
"Colon had a very good exam," said manager Terry Francona. "He's a lot less tender than he's been. The plan as of now is to wait, hopefully, two more days, and then he'll start throwing. I think that was good news. Obviously, he'll be examined before they turn him loose again, but he had a good exam."
Colon would start by playing catch before graduating to a side session.
He needs to pitch at least a few more times at Triple-A Pawtucket before being promoted. Before sustaining his untimely injury, his only obstacle to getting to Fenway was getting stretched out.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.