An MRI revealed that John Lackey has a strained right triceps and will be out of action for up to a month, the Angels announced today. Dr. Lewis Yocum had evaluated Lackey Friday and diagnosed the right-hander with the strain. The MRI, done in Scottsdale, Ariz., confirmed that diagnosis. Lackey already has started his rehab therapy and will be reevaluated in 3-4 weeks.