Grissom (hamstring) started at second base and went 1-for-4 with a double and an RBI in a rehab game for Triple-A Worcester on Sunday.
Grissom played six innings in the field before being removed. He began his rehab assignment Saturday, serving as the designated hitter and going hitless in two at-bats with two walks and a stolen base. The Red Sox believe Grissom could need close to the maximum 20 days for his rehab assignment, pushing his potential return from the 10-day injured list into the second week of August.