The NHL blocked the Buffalo Sabres from sending rookie center Mikhail Grigorenko to Rochester of the American Hockey League on a conditioning assignment.
The 19-year Grigorenko was one of four rookies sent to the minors on Tuesday, but the Sabres announced the NHL's decision on Wednesday. According to league rules, a conditioning assignment can last no more than 14 days.
The ruling forces the Sabres to keep Grigorenko in Buffalo or return him to his Canadian junior team, the Quebec Remparts. But the Remparts already have the maximum two imports and would have to make a trade to clear room for Grigorenko.
The AHL-CHL agreement stipulates that CHL prospects must remain in major junior until they are age 20 or have played four full seasons. Grigorenko is not eligible to play for Rochester full time.
Grigorenko has been a healthy scratch in five of the past seven games.
---The Detroit Red Wings placed rookie defenseman Danny DeKeyser on long-term injured reserve with a sprained left shoulder.
The shoulder will not require surgery, Red Wings general manager Ken Holland told MLive.com. But DeKeyser is expected to miss a minimum of three weeks and possibly six after suffering the injury during Tuesday night's game against Nashville on a hit into the boards by the Predators' Patric Hornqvist.
By placing the 23-year-old DeKeyser on long-term IR, he is not eligible for return for at least 10 games. The earliest he could return is Dec. 14 for a game against the Pittsburgh Penguins.
The undrafted free agent from Western Michigan was averaging nearly 21 minutes of ice time in a breakout season for the Red Wings. He has two goals and seven assists in 22 games.