Per Lakers reporter Mike Trudell, Hart injured the fourth metacarpal in his left hand during practice Wednesday.
Hart, 22, has had a solid rookie season for the Lakers, averaging 6.6 points, 3.7 rebounds and 1.2 assists in 21.5 minutes per game, shooting 39.7 percent from three. He's played both guard spots for the Lakers and filled in at point guard while Lonzo Ball was injured before the team acquired Isaiah Thomas at the trade deadline.
He's gradually taken on a larger role, averaging 12.2 points, 7.4 rebounds, 2.2 assists and 1.0 steals in 32.1 minutes in 10 February games.
While Ball was the biggest name in the Lakers' 2017 draft class and Kyle Kuzma (15.4 PPG, 5.8 RPG) has been the most productive of the team's rookies, Hart has been a pleasant surprise and has established a role for himself going forward in Los Angeles as a steady reserve.
"He's done a nice job of bringing us some more toughness," head coach Luke Walton said of Hart earlier in February, per Trudell. "His rebounding is one of the strengths of what he does, but he's even taken it to another level. He plays basketball the right way, which is what we're trying to do. He shoots it when he should shoot it, he drives and kicks when he should do that. It's been a nice little run that he's helped us go on.
In his absence, Ball and Thomas will split point-guard duties, while Alex Caruso and Tyler Ennis could see their roles increase in the backcourt.