Aside from injuries, there's only been once change in the Clippers' starting lineup this season, and that was when Matt Barnes took over the small forward slot from Jared Dudley mid-season. However, when Danny Granger was brought on board in late February, many pundits saw the former All-Star as inevitably making his way into the starting lineup eventually. In fact, Clippers coach Doc Rivers even said that Granger would "ideally" become the starter at some point.
Why not now?
Matt Barnes' play, much improved after the trade deadline, has severely dipped in the playoffs. Through four games, he is averaging 5 points and 2.7 rebounds a game, shooting under 35% from the field and 20% from deep. This is all despite the fact that he's been playing against the undersized Stephen Curry on that end. Due to Barnes' ineffectiveness, the Warriors have been able to hide Curry on defense and stick either Klay Thompson or Andre Iguodala (both elite perimeter defenders) on Chris Paul. Not only has Paul had to play against one of these defensive studs, but on the other end he has to guard Curry, who has essentially been able to conserve energy on the defensive end of the court without costing his team.
This could be easily rectified by starting Danny Granger, or perhaps just playing him with the starters more. Granger hasn't shot well from deep in the series either (3-10, 30%), but his career numbers are much stronger, leading to more floor spacing. As a 6'9" combo forward, Danny also has the post game to truly punish the Warriors if they cross-match and put Curry on him. I would assume that instead of allowing his point guard to be abused on the block, Mark Jackson would be forced to switch Curry back on to either J.J. Redick or Chris Paul, which will give the Clippers plenty of opportunity to run Steph ragged off of screens and force him to exert himself defensively.
On the other end of the court, it's a little more complicated for the Clippers. Paul will almost certainly continue to guard Curry, but Granger may struggle to stick with either Thompson or Iguodala. However, now that the Warriors are starting Draymond Green instead of Jermaine O'Neal,I would actually consider putting Granger on Green and Griffin on Iguodala.
With this first-round series tied at 2 games apiece, the California Cup is down to a best-of-three race between the Clippers and Warriors. In any 2-2 series, game 5 is always crucial, and pulling an unannounced switch in the starting lineup (or simply substituting Granger in early for Barnes) could throw an unexpected wrench in the Warriors' defensive gameplan and give the Clippers the edge they need to establish themselves early in the game.