Manu playing that bad is by far the biggest concern regarding Spurs.
It usually takes a little time for Manu to get back his groove and rhythm after an injury but, he has played 17 games since he came back from the hamstring injury and he is still struggling. It's worrying.
I certainly won't bury Manu because he is a great player but he is at an age where you had to wonder if this slump isn't a sign that he has nothing left in the tank. Manu is the fifth oldest SG/SF in the NBA behind Grant Hill, Jerry Stackhouse, Ray Allen and Vince Carter. The four wingmen older than Manu were great players that are now nowhere near their previous level.