Cooper (back) started a throwing program and began hitting off a tee Friday, Christina De Nicola of MLB.com reports.
Cooper has been cleared to resume baseball activities after he was placed on the 10-day injured list June 9 with a lumbar strain. The Marlins may want to see Cooper complete a brief minor-league rehab assignment before activating him from the IL, so he could be challenged to rejoin the big club by the end of June.