ANAHEIM, Calif. — The Los Angeles Angels will start the season without ace John Lackey, who is out three to four weeks because of a strained right triceps.

Lackey underwent an MRI in Scottsdale, Ariz., on Friday that confirmed Dr. Lewis Yocum's diagnosis.

The right-hander has already started rehabilitation and will not participate in any baseball activities until he is re-evaluated, the team said Saturday.

Lackey made his first spring training appearance last Monday, pitching 1 2-3 innings against Oakland. He said he threw without pain.

Lackey won 19 games last season and led the AL with a 3.01 ERA.