Bart (hamstring) ran on the basepaths before Tuesday's game against the Cubs, Andrew Destin of the Pittsburgh Post-Gazette reports.
Bart has been on the injured list since Aug. 26 due to a strained left hamstring, and Tuesday appears to be the first time he's done any sort of running since then. He's expected to rejoin the active roster before the end of the season, though it's still unclear how close he is to a return.