All was quiet in the Spurs' practice gym Friday morning. The lights were dim. Nary a ball bounce nor a shoe squeak filled the air. Don't mistake the calm for inactivity. Though players were given a final day off in advance of Game 1 of a Western Conference semifinal series that opens Monday, Spurs coach Gregg Popovich and his staff were holed up and hard at work on early preparations for the Golden State Warriors. Bleary eyed, and with what appeared to be about two days' growth of gray stubble on his cheeks, Popovich emerged from his office around noon to offer initial impressions of the Spurs' next opponent.