The Grizzlies were approximately 7 points/per 100 possessions worse this season against the Spurs when Randolph and Gasol were on the floor together..
In today's game, they have been more successful with Randolph on the bench, allowing them to spread the floor..
The Spurs' defensive success this season has been on the interior, with the Duncan-Splitter frontcourt anchoring the team..this matches up well with the Grizzlies style of 2 post players and no shooters to hurt the Spurs..
Bonner has also shown that he does a decent job against Randolph, while Z-Bo has no chance to contest his shot..
Duncan is also in a perfect defensive situation when Randolph is on the floor, as he can guard him without the threat of the pick and roll..
If the Grizzlies are going to win this series, they will probably have to go to Arthur more often, or go with small-ball and Prince at the 4 IMO..they should still be giving Randolph 30 minutes per game, obviously, but they should be running lineups without him more frequently, especially when he's struggling..
Of course this is all meaningless if Randolph is hot, since he's difficult to stop in that case, especially since Memphis's offensive options are scarce..