Give him a month, and maybe AFL, or something less competitive where he can still build up the ankle. Maybe two weeks at Potomac, then two weeks at Harrisburg. Then AFL on the rookie condition, like Harper's first season, when he could only play a couple games a week.
Start at Harrisburg next April, then Syracuse mid-season, then Nats in September (or sooner for the 2013 pennant to fly alongside the 2012 pennant)