Manager Rob Thomson said Walker (shoulder) will be activated from the 15-day injured list to start Sunday against the Padres, Alex Coffey of The Philadelphia Inquirer reports.
The veteran right-hander allowed four runs over 6.1 innings during his third minor-league rehab start Sunday, and a successful bullpen session Tuesday was his final hurdle before being cleared to return. Walker posted a 4.38 ERA, 1.31 WHIP and 138:71 K:BB across 172.2 innings last season for the Phillies.