I think Rondo certainly hurt them on offense on Friday (not sure about Sunday). He was out of rhythm, and the team had gotten hot by simplifying things.
However, that is somewhat irrelevant in the grand scheme of things. To me, the bottom line is this team needs another star, other than the Big 3, if they want any chance in the playoffs this year.
Rondo has fit into the offense well at times, but they seem to have lost the rhythm since the middle of last year. But, all that means is they need to find that rhythm again...and they have about 2 and a half months to do it.