I've had Jacobs two years in a row - I can confirm that 4th quarter last year. The way I remember it, Coughlin said Jacobs had a sore knee so they kept him out as a precaution...Jacobs denied and said he was 100%. Never really found out who was telling the truth there, but my guess is that Jacobs didn't want to admit he was hurt.
I'd be concerned about Jacobs in a PPR league. I don't play in a PPR so I haven't run any projections, but if the running game takes a step back since they don't have a WR deserving of regular double coverage, Jacobs won't make up the difference with receptions. He only had 219 carries last year - he helped fantasy teams by a 5 ypc average and 15 TDs. I think it is realistic to believe those numbers will decline, however he may carry the ball more often with Ward gone.
Best case scenario: More carries with a worse average.
Worst case scenario: Similar carries and the whole offense becomes less efficient and productive.