I think I said it last year, but Willis' destiny as a half-back/move TE/FB is seeming en route to being realized, and I think ultimately he'll be on the roster long after Latu is headed off to play backup in NV.
It's an overlooked spot to save money, but as much as #44 is a help, he's paid a lot for lead blocks that aren't nearly as important since #71 got to town.
Being able to take that salary and Mooney's money off-book potentially next year could be enough to more than bridge whatever they're separated with Aiyuk, for what will ultimately end up an upgrade after growing pains.