I know that's what Doc told him to do. As noted in the Herald:
A backup also won't be enough. Rondo, who tailed off at the end of the Orlando series, continued to have a major weakness exposed.
``What happened to Rajon came from the way (Orlando) played him,'' said Rivers. ``Orlando made him the player who had to beat them. They took away Ray and Paul and put it on (Rondo).
``The playoffs will always be the toughest part for Rondo, because they'll always put it on him to make shots. But he'll grow from it.''
From that, I'm assuming the team is really focusing on jump shooting with Rondo.
Good stuff. I was labelled a Rondo hater for saying the exact same thing.
A related note: Rondo is not comparable to Tony Parker in his evolution re: jump-shots. In his 3rd season, Parker took around 650 jumpers (40% eFG), including 200 triples. Rondo took 320 jumpers (37% eFG) and 48 triples. Very different games; teams were guarding Parked differently than they're guarding Rondo now.
I've said these many times already, but I believe that if Rondo becomes a passable shooter (for a guard), the Celtics would be the best offensive team in the league.
Answering the question from the OP, I don't know if it's enough. However, I think Rondo needs to work with a "jump-shot doctor", not by himself or with some random trainer.