An offseason of change for the Gophers men’s hockey program continued Monday when freshman center Casey Mittelstadt, the team’s most dynamic offensive player, agreed to contract terms with the Buffalo Sabres.

Mittelstadt’s decision follows last week’s major developments that included the resignation of coach Don Lucia after leading the program for 19 years and the departure of sophomore defenseman Ryan Lindgren to sign with the New York Rangers organization.

Mittelstadt, the No. 8 overall pick by Buffalo in last year’s NHL draft, agreed to a three-year, entry-level contract with the Sabres, the team announced. He is expected to sign his contract Tuesday and said he is scheduled to make his debut in Thursday’s home game against Detroit.

“I always wanted to be a pro hockey player and I get the chance to play in the NHL, and it was too good a thing to pass up,’’ Mittelstadt said Monday night from Buffalo.

The Eden Prairie High School product and 2017 Minnesota Mr. Hockey ranked second on the Gophers with 30 points (11 goals, 19 assists) in 34 games this season and earned Big Ten all-freshman honors. He had two game-winning goals and took a team-high 511 faceoffs, winning 49.1 percent of them.

Mittelstadt said it wasn’t easy leaving the Gophers.

“Any time you get to know guys like that and get to play with a storied program like that, to me it was a dream to play there,’’ he said. “I’m going to miss it, but I think I made the right decision for myself and my career.

“… I honestly tried to weigh both options to make sure I had both feet in,’’ he added. “As I continued to think about it, both feet were here.’’

The 6-1, 201-pounder was a standout in the World Junior Championship in January, earning MVP honors after tying for the scoring lead with 11 points on four goals and seven assists.

Mittelstadt led Eden Prairie to four consecutive state tournament appearances and was the Star Tribune’s Metro Player of the Year in 2017 after amassing 23 goals and 49 assists in 72 games.

Mittelstadt is the fourth Gophers first-round draft pick since 2006 to leave after his freshman year and sign with an NHL team, joining Phil Kessel (2006), Erik Johnson (2007) and Nick Leddy (2010).

With Mittelstadt gone, the Gophers will have a hole to fill following a 19-17-2 season that saw them miss the NCAA tournament. As of now, they return the other four of their top five scorers — current sophomore Rem Pitlick (12-19—31) and juniors Brent Gates Jr. (12-14—26), Tommy Novak (2-23—36) and Tyler Sheehy (12-13—25). A rebound season by Sheehy, who earned All-America honors in 2016-17 with a 20-goal, 33-assist season, would help offset Mittelstadt’s departure.

In addition, incoming freshmen could help a Gophers offense that averaged 2.63 goals per game (39th of 60 teams nationally). Though the new coach will have the final say, among those expected to join the team next season are Edina’s Sammy Walker (35 goals, 44 assists this season), Blake McLaughlin (47 points in 48 games for Chicago of the USHL) and Garrett Wait (39 points in 51 games for Waterloo of the USHL). Connor Hurley, a transfer from Notre Dame, could help, too. He had 16 points in 21 games for the Fighting Irish in 2016-17.