Second-round leader Watson fended off charges from Hoffman and DeLaet on the back nine until carding a bogey 5 on the 17th to drop to 10-under.
He ended with a par on No. 18 for round of even-par 70, finishing 54 holes at 10-under 200.
Watson, seeking his first PGA Tour win since taking the 2012 Masters, settled for a share of the top spot with first-round leader Hoffman (4-under 66) and DeLaet, whose 5-under 65 tied for the low round of the day.
Ken Duke (69) held sole possession of sixth at 8-under.