The Sabres returned the 6-foot-1, 185-pound center, the second pick of the 2014 NHL Draft, to his junior team, the Kootenay Ice of the Western Hockey League, on Friday.
"The minutes he got here, the situations he played in here, suggested to me it was time to get back," Sabres general manager Tim Murray said.
The Sabres could play Reinhart in nine games before deciding whether or not to keep him beyond his 10th game and start the clock on his three-year, entry-level contract or return him to junior hockey. Reinhart played his ninth game against the Boston Bruins on Thursday; the Sabres' next game is Saturday against the Pittsburgh Penguins.
"He's not going to learn a whole lot there on the ice, I don't think," Murray said. "I told him I know he can go back there [Kootenay] and be a 120-point guy in a full season playing three-quarter speed, but that's not what we want him to go back there and do. We want him to get stronger and he's going to have to find a way to … find a way to slip out on his own to get to the gym and get stronger."