I think this is the rationale: In sports (or anything that requires practice), going some time without practicing actually makes you lose some of the ability you once had. So in this case, it would take two practices just to get back what was lost during the break, at which point he would be 4 practices behind.
So the issue is regression. I can believe that, but the original story didn't get that across clearly. Though I imagine the concept was familiar to the players, so it was probably clear at the time.
