First, Derrick White. Then, Jayson Tatum. Now, Sam Hauser.

The Celtics locked up yet another of their 2024 champions on Sunday, reportedly signing reserve wing Sam Hauser to a four-year, $45 million contract extension. ESPN’s Adrian Wojnarowski was the first to report Hauser’s deal. Hauser already was set to return for the 2024-25 season after Boston picked up his $2.

1 million team option last month. His new contract will start in 2025 and run through the 2028-29 campaign. The 26-year-old Hauser joined the Celtics as an undrafted rookie in 2021 and developed into one of their top bench contributors.

He appeared in 79 regular-season games and all 19 playoff games last season, setting career highs in most statistical categories. His greatest asset is his 3-point shooting. Hauser’s 42.

4% shooting percentage from three in 2023-24 ranked 11th in the NBA and seventh among players who averaged at least five 3-point attempts per game. Hauser shot 44.6% from the field and averaged 9.

0 points and 3.5 rebounds per game. The Virginia product struggled at times during Boston’s playoff run — especially in the Eastern Conference Finals, during which he went 1-for-14 from deep — but redeemed himself in the NBA Finals.

He made 47.8% of his threes in the five-game win over Dallas while playing surprisingly competitive defense against Mavericks superstar Luka Doncic. In the weeks between the NBA Finals and Hauser’s new deal, the Celtics finalized long-term extensions for White (fo.