BUFFALO — What’s Sabres defenseman Marc-Andre Gragnani capable of producing over a full season? Fifty points perhaps? Were the rookie’s late-season heroics just a fluke? Can he continue his clutch play? The Sabres will find out soon, as the 24-year-old Gragnani, their last restricted free agent, accepted his qualifying offer Thursday, agreeing to a one-year, two-way contract. “We couldn’t find common ground on a longer-term deal,” said Kent Hughes, Gragnani’s agent. In the midst of his dazzling AHL campaign in Portland, Gragnani joined the Sabres for good in late March and immediately began turning heads. He assisted on the game-winner in his first contest, and then scored the overtime clincher four days later, his first NHL goal. His progression hit warp speed in the postseason, when Gragnani led the Sabres with six assists and seven points while skating 21:54, third on the team. Gragnani had only one goal and three points in 15 NHL games before the playoffs. “He’s a point-producer offensively, and it sometimes makes it a little bit trickier to figure out what the life of the deal is if somebody lacks experience but has a certain skill set that the league has rewarded,” Hughes said. Gragnani rejoins a crowded blue line that has seven other NHL regulars from last season. The Sabres have 24 players under contract. Before Gragnani’s deal, they had a $67,895,357 payroll, according to capgeek.com, a whopping $3,595,357 over the $64.3 million salary cap. They have until opening night to get under. Gragnani made a prorated $500,000 last season. The Sabres quietly let Gragnani, the 87th overall pick in 2005, develop four years in the minors. They converted him to a winger as a professional rookie with Rochester in 2007-08, and he made his NHL debut up front later that season. Gragnani was switched back to defense the next season in Portland, and he began performing dynamically, accumulating 33 goals and 154 points over the next three seasons, including 12 goals, 60 points and a plus-22 rating in 63 games last year. He was named an AHL First-Team All-Star and also earned the Eddie Shore Award for the league’s top defenseman.