Pretty sure no one posted this. Here's the most important snippet.

Billups’ injury breaks up the single most effective five-man lineup that has logged at least 100 minutes so far this season, according to Basketball Value. In 255 minutes together — more time than all but five units league-wide — the Clippers’ starting lineup has outscored opponents by nearly 18 points per 100 possessions. It has provided consistently great defense for a team that has done poorly on that end. Substitute Williams for Billups, and that number drops to about 4.5 points per 100 possessions. As John Schuhmann pointed out at NBA.com, the drop-off has come on defense, where Williams, at 6-1, just cannot defend shooting guards, even though he’s in the best shape of his career and generally working his tail off.