Rondo didn't play horrible against Blazers . But it's the same old story as when he arrived .
He just doesn't make a big difference either way.     He comes in,    they don't play Rondo style basketball .  
Mavs try and move the ball looking for a shot .   Never hold the ball.  So it gets passed to Rondo , who reluctantly shoots , mostly wide open shots because he doesn't draw heavy defense around the arc.
Dirk is key.   If he isn't putting up curry type of number scoring .   30 points a game ,   I don't see how the Mavs win with only games of 17 and 10' out of Dirk .    That's no Al Star production to beat LeBron.
Last 8 games Dirk is shooting 40 % .    He is playing like a very good player .   That's not gonna get it done.   He has to be great for Mavs to beat the top 12 teams in the league consistently .  Mavs mostly beating under .500 teams .   They look weak ,  no where near there normal output against a good team.   That's not gonna beat LeBron 
Rondo is NOT the scoring punch punch Mavs needed.    He is only average at best what he brings to this team