NEW YORK -- The Yankees and Pirates are continuing discussions about a trade that would end right-hander A.J. Burnett's turbulent tenure in pinstripes.

Pittsburgh is among four clubs that has reportedly shown interest in dealing for the 35-year-old Burnett, who helped the Yankees win the 2009 World Series but has followed with two inconsistent seasons.

A source told MLB.com that of the teams showing interest in Burnett, Pittsburgh appears to be the most likely trade partner. The Yankees are willing to pick up part of the $33 million Burnett is owed over the next two seasons, the remaining portion of a five-year, $82.5 million contract signed before the '09 season.

Furthermore, another Major League source portrayed the Pirates as being "optimistic" of eventually working out a deal, with only "the money and players exchanged" yet to be determined. In return for raising the amount of Burnett's contract they would be willing to undertake, the Pirates would expect a discount in the prospect or prospects the Yankees seek in return.

New York and Pittsburgh are said to still be haggling over the exact dollar amount that will be handled by the Yankees in the deal, which could exceed $10 million, as well as what players the Pirates would surrender in return.

ESPN.com reported that the Yankees have asked for first baseman and outfielder Garrett Jones, but that request was rejected by the Pirates.

While the Yankees originally pursued Burnett to serve as a one-two punch with CC Sabathia at the head of the rotation, two unsatisfying seasons with thick ERAs have pushed him further back on New York's depth chart.

Burnett is 34-35 with a 4.79 ERA in his three seasons with the Yankees, and his combined 5.20 ERA for 2010 and '11 has deleted patience from the grandstands.

Part of Burnett's troubles may stem from his diminished fastball velocity; Burnett spoke honestly on at least one occasion about how he felt hitters no longer were uncomfortable standing in against him, suggesting he needed to learn to pitch inside more.

However, Burnett did harness his command and repertoire to pitch well in a crucial American League Division Series start, helping send the series back to New York with a Yankees win in Game 4 at Detroit.

Despite his 11-11 record and 5.15 ERA, last season represented something of a bounce-back year for Burnett, considering his multiple issues in 2010.

That season, Burnett clashed at various times with catcher Jorge Posada, sliced the palms of his hands attacking a Yankee Stadium clubhouse door in July and pitched a September game in Baltimore with an unexplained black eye.

The Yankees have largely supported Burnett, but they also currently have seven starters to fit into five rotation slots. That figures to have Burnett heading to Spring Training competing with Phil Hughes and Freddy Garcia to serve as the fifth starter.

At the moment, the Pirates also have a full rotation, but that includes Charlie Morton, whose season-opening availability is in question after he underwent hip surgery in October. Pittsburgh's other starters are Erik Bedard, signed as a free agent, and incumbents James McDonald, Kevin Correia and Jeff Karstens, also a former Yankee.

Beyond the Morton uncertainty, the Pirates' interest in Burnett reflects their hope that a return to the National League could energize the career of the right-hander, who has struggled primarily with inconsistency since leaving Florida as a free agent after the 2005 season.

Yankees general manager Brian Cashman has acknowledged that he would listen to trade offers for Burnett, while lauding the fact that despite Burnett's struggles, he has not been on the disabled list with New York and has been a reliable innings-eater.

Burnett's contract with the Yankees includes a list of 10 teams he cannot be traded to. The New York Post reported last week that all of those clubs are on the West Coast; Burnett's wife, Karen, dislikes flying from their Maryland home.

Through seven seasons with the Marlins, Burnett crafted a career ERA (3.73) he never reached in any of the six years he spent in baseball's toughest division with the Blue Jays and the Yanks.

The Yankees are also interested in acquiring a left-handed bat to help out in the designated hitter role after dealing top prospect Jesus Montero to the Mariners in January, but it is thought the club only has about $1 million to $2 million to spend in that area.