Jerome Williams strains hamstring

TEMPE, Ariz. -- Los Angeles Angels pitcher Jerome Williams, the frontrunner to be the team's fifth starter, strained his left hamstring during a defensive drill Friday and was examined by a team doctor.

The Angels said they don't yet know the severity of the injury, but that Williams will be re-examined Saturday morning.

If Williams is out for an extended period and opens the season on the disabled list, rookie Garrett Richards could be in line to replace him in the rotation.

The Angels also have Trevor Bell, Eric Hurley and Brad Mills, each of whom has major-league experience, in camp.

Williams, a first-round pick of the San Francisco Giants in 1999, was 4-0 with a 3.68 ERA in 10 appearances last year. The Angels signed the right-hander, who had pitched in Taiwan and independent ball, last June.

Mark Saxon covers the Angels for ESPNLosAngeles.com.