Spurs coach Gregg Popovich and his staff have a well-earned reputation for developing players, something not lost on McCallum.
"Player development is huge, especially in the NBA," McCallum said. "I feel like I have a high ceiling and I'm glad to be here with these guys, and I think they can really expand my game. It's something I really haven't had in my first two years. I'm going to be around some great players and great coaches, and be in a great system. I'm excited to see where I can take my game."