A top NHL coach has highlighted a pressing challenge for teams under the league’s new collective bargaining agreement, noting that the window for roster adjustments is tighter than ever. With the season set to begin soon, the constraints on player transactions—particularly for those meeting specific service-time thresholds—could force clubs to make critical decisions earlier than in past years. The shift may impact how teams build their lineups and manage their talent, as the rules now limit flexibility in addressing injuries or performance issues. Experts suggest the changes could reshape how franchises approach their opening-night rosters.

Washington Capitals coach Spencer Carbery, whose team plays its opener at Carolina on Oct. 2, pointed out that the runway is even shorter than that, though. Under the new CBA, players with at least ...