How Long Will It Take To Recover After Tibula Fracture?

My son is 17 and has a minor non displaced fracture of the tibula. The dr. put him in a boot for 4 weeks and said he should be healed by then. He is puting ice on it 2-3 times a day and moving it front to back as well (as directed by dr). My question is how long should he expect to be able to run after removing the boot? He is a baseball player (center fielder) and he is just wanting an idea of if he will even be able to play this season. Thanks