Yes, I think they keep four. Don't think they would have signed Jacobs if they did not see a use for him. The trick during camp will be to hedge against injury at each posiiton. So players who have flexibility will have an edge at many positions and RBs can usually be useful on STs.
For those who didn't like the James pick--go back and check his college stats. They aren't just good they are eye popping--many 200+ games. He will add an element of excitement the niners have lacked. As much as I like Hunter, he is more a ball control type all-purpose back, James is an explosion waiting to happen.
With the addition of James and Jenkins I think Ginn may be the odd man out. They may be able to replace him on ST and at WR/RB (more effective on the reverse than as a receiver). Would hate to see this as he was so dependable and that is hard to find but..such is life!
[ Edited by dtg_9er on May 2, 2012 at 6:31 AM ]