UPDATE (3:52 p.m. ET) Jaylen Brown and the Boston Celtics have resolved their differences.
Brown has agreed to a four-year, $115 million contract extension with the Boston Celtics hours before Monday's deadline, the team announced.
The $28.75 million-per-year deal will keep Brown in Boston through 2024 and makes him the third-highest-paid Celtic behind Kemba Walker and Gordon Hayward.
Brown is the first Celtics player to earn an extension off his rookie deal since Rajon Rondo in 2009.
ORIGINAL STORY: Jaylen Brown and the Boston Celtics are at an impasse, it appears.
There's "no final resolution" between Brown and the Celtics on a possible contract extension ahead of Monday's 5 p.m. ET deadline, The Boston Globe's Adam Himmelsbach reported Monday afternoon.
Celtics president of basketball operations Danny Ainge confirmed last week the team has made several extension offers to Brown, who is entering the final year of his rookie deal.
Brown reportedly rebuffed a four-year, $80 million offer from Boston recently while holding out for a richer deal.
The 22-year-old took a step back last season, averaging 13.0 points, 4.2 rebounds and 1.4 assists per game after a strong sophomore campaign.
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Several members of Brown's 2016 NBA Draft class, meanwhile, recently have agreed to lucrative extensions -- most recently Sacramento Kings guard Buddy Hield, who reportedly inked a four-year, $86 million deal worth up to $106 million with incentives.
If Brown and the Celtics can't come to terms before 5 p.m. ET, he'll become a restricted free agent in a 2020 offseason that features a relatively weak free agent class.
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