Shields (shoulder) will embark on a rehab assignment Saturday, Scott Merkin of MLB.com reports.

EDGE Analysis

Merkin relayed what pitching coach Don Cooper told the TV broadcast Tuesday. It is unclear what level Shields will begin his rehab assignment at, or how many rehab starts he will require before rejoining the big-league rotation. He threw a 30-pitch bullpen session Friday and threw a simulated game Monday. Shields posted a 1.62 ERA, 5.25 FIP, 1.14 WHIP and 16:10 K:BB in 16.2 innings prior to suffering the injury.