Although Chatwood is due to come off the 60-day disabled list on June 29, his return is unpredictable because it is not certain how the tendon -- which is near the elbow -- will respond when he begins competitive pitching.
"I think we've done everything we can," Chatwood said. "Going forward, if there is a setback, we've done everything within our control. I feel confident going forward."
Also, left-hander Brett Anderson, who sustained a broken left index finger on April 12, had the pins (which were inserted to aid in healing) removed on Tuesday. Anderson will undergo flexion and grip exercise before beginning a throwing program. Anderson eligible to come off the 60-day DL June 12, but his timetable has him returning possibly in early July.
Thomas Harding is a reporter for MLB.com. Follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.