Why would Parker guard Ellis?

..
Being able to hide Parker on Rondo is huge for this matchup, he
had a lot of trouble against Harris and
Calderon last year..the Mavs don't really have any mismatches to exploit in the starting unit..Dirk has been mediocre and is slower than ever, too, he's going to struggle if Splitter continues his offensive breakout week..
Mavs best chance is their bench vs. the Spurs bench without Ginoboli..Harris/Barea/Aminu/Amare could give the Spurs some issues..they'll also be fired up after Carlisle called them out for an embarrassing performance..