Martinez (foot) has shed his walking boot, is playing catch and hitting off a batting tee, Tim Stebbins of MLB.com reports.
It's encouraging that Martinez has begun baseball activities already, but there's been no word his four-to-six week timeline has been adjusted. That likely means a return after the All-Star break. The 24-year-old switch hitter has a career-high .718 OPS, 11 homers and nine steals through 66 games this season.