Could be calling 22,33,44,55,1010, A10, AQ, 54h which all have me beat. Also could have Ax of hearts which improved to 2 pair.
only other hands be bet here is a busted fd? maybe he is value betting a worse ace? although 15/11 pretty tight not a ton of smaller aces in his range, maybe Ax of hearts. But would he value bet that here? probably not