The New York Knicks continue to dangle Iman Shumpert in trade talks, including a recent proposal to the Celtics that would send the third-year guard and Amar'e Stoudemire to Boston in an effort to obtain star point guard Rajon Rondo, league sources confirmed Sunday.

The Celtics, though, have yet to show interest in the deal, instead preferring to unload forward Gerald Wallace in a trade, sources said.

The Knicks have inquired about Rondo in trade talks before, but both times the Celtics made it clear they were not interested in trading him.

Rondo currently remains sidelined while recovering from February ACL surgery.

Sources did say the Celtics would be willing to take on Stoudemire's contract if they could unload some of their longer deals, namely those of Wallace and Courtney Lee.

The Knicks may be reluctant to take Wallace back because they're hesitant to take on salary beyond the 2014-15 season.

The Knicks have three large contracts (Stoudemire, Tyson Chandler and Andrea Bargnani) coming off their books at the end the 2014-15 season and would like to be in position to acquire a top-flight free agent.

A trade including Wallace and Stoudemire would seem to benefit the Celtics financially. Boston is in rebuilding mode, and Stoudemire's contract expires a year before Wallace's.

One factor that could complicate trade talks involving Shumpert is that the 2011 first-round pick had a second surgery on his left knee this summer, league sources confirmed on Sunday.

A source with knowledge of Shumpert's surgery described it as a minor procedure.

Shumpert's knee surgery and the Knicks' attempts to trade a package including him to Boston was reported earlier Sunday by the New York Daily News.

Shumpert had surgery following his one-game stint in the Las Vegas Summer League in July, sources said.

One league source with knowledge of the team's thinking said that some in the Knicks' organization were upset by the timing of Shumpert's surgery because they felt he could have had it earlier in the summer.

Knicks coach Mike Woodson said in October that Shumpert came into training camp a bit out of shape and suffered pain in his knee in the offseason.

Shumpert had surgery to repair the left ACL and meniscus in his left knee in April 2012. He spent seven months rehabbing. So the fact that Shumpert had a second surgery on the same knee may be a red flag for teams interested in trading for him.

The Knicks and Nuggets discussed a Shumpert-for-Kenneth Faried swap last week. New York believed it had a deal completed on Tuesday morning, a league source told ESPNNewYork.com. But the trade fell through when Denver asked the Knicks to include at least one draft pick.

The Knicks are in search of frontcourt help to help ease the burden of the injured Chandler, who is expected to miss at least three more weeks with a fractured right fibula. The Knicks (3-6) are comfortable dealing Shumpert for help on the front line because they believe J.R. Smith and rookie Tim Hardaway Jr. can fill their needs at shooting guard.

The Knicks have tried to move Stoudemire several times over the past year. But teams are hesitant to take on his contract ($45 million this year and next) and history of knee issues. Stoudemire is currently playing on a minutes limit to protect his oft-injured knees. Stoudemire had three surgeries on his knee in a 10-month span and his contract is uninsured due to a long history of knee ailments.

Information from ESPN.com's Brian Windhorst and Chris Broussard was used in this report.