WASHINGTON -- All winter and all spring, the Mets insisted they had little interest in sending their top prospect, Pete Alonso, back to the Minor Leagues. If Alonso deserved a roster spot, general manager Brodie Van Wagenen said, then he would be there on Opening Day.

So it came to be that Alonso flew this week to Washington, where he is set to be with his teammates for Thursday's opener. Van Wagenen confirmed on Wednesday afternoon that Alonso made the team. And not only that, a source tells MLB.com that Alonso will be in the starting lineup at first base for Thursday's opener against the Nationals and Max Scherzer.

“I do want to focus on winning games,” Van Wagenen said. “Let’s win as many as we can as early as we can early in the season.”

Alonso, the Mets' second-round draft pick in 2016, hit .352 with four home runs, five doubles, a triple and a 1.006 OPS in 22 Grapefruit League games. That production came after he batted .285 with 36 homers and a .975 OPS over two Minor League levels last season.

“I think he’s got the most power I’ve ever seen,” teammate Jacob deGrom said.

Due in part to Alonso's defensive limitations, the Mets decided not to call him up last season, keeping his service time an issue heading into the winter. Major League rules stipulate that if the Mets had kept Alonso in the Minors for approximately the first two weeks of this season, they could have gained an extra year of team control over him, delaying his becoming a free agent until after the 2025 season. But team officials insisted all spring that they intended to carry the best 25 players north with them. Alonso was one of those 25.

“I’m not of the mindset that we should be sacrificing the best product for the fans or the best product for the other 24 guys in that clubhouse to save service time or potential future money six years down the road,” Van Wagenen said. “If Pete Alonso or anybody on our roster is good enough to have six consecutive years without having a hiccup, or without ever having to go to the minor leagues, that’s a good, high-class problem for the player. It’s a high-class problem for the organization.”

Nonetheless, the status of top prospects such as Alonso has been a matter of significant debate in recent years. Most prominently, the Cubs and Braves held down superstars Kris Bryant and Ronald Acuna Jr. at the beginning of their rookie seasons, ensuring extra seasons of team control. Before Vladimir Guerrero Jr. suffered a spring injury, the Blue Jays announced they would start their top prospect in the Minors. The White Sox likewise demoted Eloy Jimenez this spring, before undoing the transaction when they signed him to a contract extension.

But the tide may be beginning to turn. In addition to Alonso, Padres top prospect Fernando Tatis Jr. is expected to start this season in the big leagues.

“When players perform and earn opportunities, we as an industry, and certainly the New York Mets, will reward those players for those performances,” Van Wagenen said. “Pete Alonso is a player that had a tremendous year last year. He had a great Fall League. I spent a lot of time with him this offseason letting him know there was an opportunity for him to make this club if he was one of the best 25 players in our organization. And I think he showed us, and he certainly showed his teammates, that he was one of those 25 guys. And he earned it.”

Alonso’s assignment to the roster will not come at the expense of Dominic Smith, who also made the club. Those two will split playing time, with Alonso to start against Scherzer on Opening Day and likely Patrick Corbin on Sunday. Smith could play the game in between, versus right-hander Stephen Strasburg.