Locke suffered a concussion during Sunday's 27-23 win over the Colts, Todd Archer of ESPN.com reports.
Locke was able to clear concussion protocol and play in Week 9 after suffering a concussion in Week 8 against the Cardinals. The safety now appears to have picked up a concussion in a second straight game. Locke will have an uphill battle to be available for Week 10 against the 49ers, and if he misses that contest, Markquese Bell would be a top candidate to draw the start at strong safety.