Duffy (hamstring) took ground balls Sunday, and manager Kevin Cash reported the session went well, Juan Toribio of MLB.com reports.
Duffy had a productive weekend, as he'd also ran at 80 percent intensity Saturday. The oft-injured infielder clearly emerged from that activity without setbacks, considering he was able to return to the field for Sunday's workout without limitations. Cash mentioned the team will continue to be cautious with Duffy's game action, but he confirmed the 28-year-old will try running at 90 percent Monday as the next step in his rehab.