I don't have a source for this information right now, but i heard that we'll be able to acquire all four Team Captains this cycle and not have to be forced to choose.  That being said, Frank the Tank is the obvious choice for a 49ers fanatic / theme team.

was just confirmed on the EA stream, kangfirmed all four Team Captains are available to us (and upgradable, from 80-85 OVR).