Wollenman is already on academic scholarship and he is a senior. The bench is about to be shortened and there's a couple guys on scholarship now that might not play more than a few minutes the rest of the season, Izzo likely already knows who is transferring and they've talked about it. It's assumed that Ellis is the one who will transfer, but what about Ahrens? He has to see the writing on the wall that he's never going to see the court on a team with this much talent and his injuries are still a factor, he could transfer while he is still young and have a great career at a mid major.
Regardless, Izzo knows his scholarship situation and would accept a commitment from Jackson today, they don't have to be at 13 scholarships until late summer of 2016. It wouldn't surprise me if the transfer has already agreed to transfer.
And Jackson is a special player, he can do it all and would be the best player in the country next year. What separate him from other #1 players is he loves to play defense, he's a lock down defender and plays tough. He, Langford, and Bridges together would make for the most athletic 2, 3, and 4 the conference has ever seen, it would be a highlight reel every game. This isn't just any old #1 player, this kid is a once in a decade type talent.