The two stars had planned for weeks on meeting up for a meal when the Lakers were in Boston, sources told ESPN.com.
While there are no active talks between the two franchises involving a trade for Rondo, sources said the teams did have a brief discussion a few months ago.
It's not clear which team initiated the call.
Rondo will be a free agent this summer, and sources stressed that the Celtics would prefer to re-sign him.
Their willingness to engage in talks regarding Rondo is merely informational at this point, sources said.
However, the Lakers have long held interest in the point guard, who helped Boston defeat them in the 2008 NBA Finals as a rookie, and sources indicate he is high on their list of free-agent targets this summer.
Should the teams re-engage in discussions about Rondo, sources indicated Boston likely would ask for at least one first-round draft pick.
The Lakers owe their own first-round pick to the Phoenix Suns unless it falls within the top five picks. They also own Houston's first-round pick.
The Lakers could include Steve Nash, who has been ruled out for the season with a back injury. Nash is making $9.7 million this season, the final year of a three-year contract with the Lakers.
However, league sources indicate the Lakers have thus far been reluctant to engage in discussions including their first-round draft picks after working so hard this past offseason to acquire a pick this season.
Rondo's injury history makes it even less likely they'd part with one of their picks for a player they could simply sign as a free agent this summer.