How many points do the Kings allow when each player is on the court as opposed to otherwise? Also, is there a synergistic effect with both players on the floor?
-4.4 offensive rating differential own team and opposition (Rudy)
+11.4 offensive rating differential own team and opposition (Cousins)
+13.2 offensive rating differential own team and opposition (Casspi)
-8.1 offensive rating differential own and opposition (Belinelli)
There's only a synergistic effect in that Rondo needs Cousins to survive, not the other way around. Rondo being a non-scoring threat actually hinders Cousins' game and offensive efficiency - i) Cousins is forced to carry too much of the scoring load ii) Rondo's man gives him more of a shooting cushion to stay closer to Cousins or a teammate. That's not to say Rondo doesn't give him good looks or easy baskets throughout the game (I mean if you handle the ball more than anyone else, you're going to get players good looks from time to time), it's just saying overall his playing style is a detriment to not only Cousin's offense but also the Kings'.
In addition when a player starts out the game they may withstand the other teams starters to the tune of -5 pets however at the end of the game in crunch time they may put up a +6.
There's a lot of noise and EaF in on/off court numbers, but the top players that actually have an impact on the game always have not only positive ratings but also they separate themselves from the rest of the league. Rondo's has POOR on/off numbers and dominates the ball while leading poor offensive-rated teams (in Sac, Dallas and Boston - there's a trend here - not an anomaly) when he's heralded as this player who makes his teammates better. It couldn't be more further from the truth. His style hurts his team - it doesn't make them better. He's carried by good/great offensive players, and when they don't play (Cousins missing games this season) his ineffectiveness rears its ugly head again.