Can I Play Base Ball After Knee Surgery?

my son suffered an injury to his right knee(torn acl) in vernal utah. This was done running the bases during a baseball game. It has been one week since this accident. He is 14 years old and we have an appointment to see an orthopedic surgeon on August 17,2011. We were told in Utah that he should continue to try and use the right knee and regain full mobility. He is very active and wants to continue to play baseball ater surgery. what can we expect?