About 12 weeks, during which time you will have become completely deconditioned, and then you will have to run very carefully for a loooong time to keep from reinjuring it. For future reference: you cannot run through a muscle tear injury like you can a sore ligament, tendon or joint. At first sign of a tight muscle which might signify the beginning of a tear, slow down, walk, or stop, whatever it takes to stop the pain, then assess the problem very carefully.