My impression is that he has not been "signed" but - along with 2 other guys - is "trying out" for an off-season roster spot.
What our eyeballs tell us from when he was with us a couple of years ago was that he (a) was a huge disappointment, (b) wasn't good enough to start and (c) was overpaid.
What we don't know is (a) whether he was impeded by injury, (b) whether he's now healthy, (c) whether he's in shape, (d) whether part of the problem before was bad karma with Dennis G, (e) his comparative value as a backup OT, (f) whether he'll be better motivated under Russ G's oversight, (g) whether he has anything left in the proverbial tank and/or (h) his value as a mentor to our younger linemen (i.e. Maybe he winds up an assistant O-line coach to Russ G).
Unless Ollie is stealing reps from other guys more likely to earn a roster spot, having him in here at the very least "can't hurt."