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"Main sticking point" emerges in what could be holding up Celtics' blockbuster deal

Can they come to an agreement?

The Boston Celtics are swinging for the fences in the day leading up to the trade deadline, reportedly targeting Chicago Bulls star Jimmy Butler.

NBA TV's David Aldridge is reporting that talks are very real (to him) between the Celtics and Bulls, and the main sticking point is on Jae Crowder.

He's the guy the Bulls are reportedly insisting on in any package. Chicago's ideal package reportedly includes a starting-caliber player and a top-half-of-the-lottery pick.

Celtics general manager on the other hand, would like to keep Crowder, Avery Bradley and Marcus Smart to balance the offensive firepower of Isaiah Thomas, Al Horford and Butler.

Yahoo!'s Adrian Wojnarowski previously pointed out the main part in a potential Butler swap is one (probably not both) of the 2017, '18 Brooklyn Nets picks the Celtics currently hold.

The 2017 selection could be as high as the top overall pick as Brooklyn is at the bottom of the NBA standings. Getting that pick could ensure the Bulls replace Derrick Rose with a franchise guard in Washington's Markelle Fultz or UCLA's Lonzo Ball.

The Celtics tried to trade for Butler at the deadline last season, and they unsuccessfully tried again during the 2016 NBA Draft.

Earlier reports had the teams discussing options that Boston could move, which include guard Marcus Smart, forward Jae Crowder and the 2017 and 2018 Nets picks.