Stephen Jackson was worthless for us last year, period. Anyone saying otherwise is fooling themselves -- he was literally the Spurs' worst player last season. Worse than Baynes, worse than De Colo, worse than Neal, worse than Anderson. He had the team's lowest PER, TS%, eFG%, offensive rating, as well as one of the highest TO% (behind only Diaw, Anderson, Baynes, and De Colo), all while eating up a huge portion of possessions when he's on the floor (18.7%, behind only the Big 3, Neal, and garbage-time players whose numbers are skewed) and only contributing middling defense (8th on the team in defensive rating, 10th in defensive win shares).
He was the only Spur to have a negative offensive win shares rating, and had by far the fewest win shares per 48 minutes. Jackson was awful last year.