MIAMI -- Rockies right-hander Tyler Chatwood, who sustained a left hamstring strain Friday during his last Spring Training appearance, threw a side session on Sunday, but whether he'll make his first scheduled regular season start on Wednesday against the Marlins is uncertain.
The Rockies will evaluate Chatwood again on Monday. If he doesn't make the start, the club will place him on the 15-day disabled list.
Chatwood sustained the injury while running the bases Friday night against the Mariners at Peoria, Ariz. Although Chatwood said Saturday he felt good and shouldn't miss a start and reported feeling fine after Sunday's session, the Rockies weren't committing to anything.
If Chatwood needs to go on the disabled list, the team likely will go with righty Jordan Lyles, who pitched well in camp (0-1, 3.18 ERA, 12 strikeouts, six walks in five games), but was edged out for the fifth starter slot by lefty Franklin Morales. Lyles last threw in a Spring Training game on March 22. He threw informally at the Rockies' complex in Scottsdale, Ariz., on Saturday.
Also, righty Juan Nicasio, who will start Thursday against the Marlins, threw at the Rockies' complex on Sunday to stay on schedule.
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.