Darcy Regier got to know Mikhail Grigorenko the past three months as a player and person. The Sabres’ general manager believes Grigorenko will grow into a top-line center who will shine in Buffalo. The 18-year-old isn’t ready to do that now, however. The Sabres sent their top prospect back to the Quebec Major Junior Hockey League on Friday, temporarily ending his NHL stay after 22 mostly uneventful games. “There’s been benefits for us,” Regier said in First Niagara Center. “There’s benefits for him. We got to know his game. He got to know us. He has a very good understanding of what he needs to do, and he gets to go back and he’s going to have the opportunity to practice and work on those things.” Grigorenko had one goal and five points while averaging just 9:44 of ice time. He impressed the Sabres during a brief training camp after putting up 29 goals and 50 points in 32 games with the Quebec Remparts. The junior team has one regular-season game remaining before starting the playoffs. “It is big news and a big surprise for us,” a Remparts spokesman said by phone.