I'm not sure what the recovery time is in softball and it may depend on the severity of the injury but torn ACLs in football and baseball are nearly always season ending injuries with 9 months the general turn around time to return to the field as a player.Whitney is fantastic. I read that she can rehab starting around 3-6 weeks (actually rehab starts when you wake up from surgery) practice in about three months.
I'd be shocked if she returns to the field before next fall as player.