Chauncey Billups continued to make strides in his comeback from tendinitis in his left foot, going through a strenuous workout Sunday morning. But there is no timetable for his return to the starting lineup, according to Clippers coach Vinny Del Negro. Billups has missed all but three games this season. Del Negro said there is no firm schedule for Grant Hill, who was available to play Sunday after playing limited minutes in Saturday's loss at Portland. Hill, a 40-year-old forward, missed most of the season because of a bruised right knee.