Dahlin left Wednesday's practice before its conclusion due to an undisclosed injury, per Lance Lysowski of The Buffalo News.
Dahlin was hurt while attempting to make a pass. It's not known yet how significant the injury is, but Dahlin is a huge part of Buffalo's blue line, so if he misses time in the regular season, that would naturally leave a significant hole for the Sabres to deal with. In that scenario, Henri Jokiharju might see an increase in even-strength ice time while Bowen Byram or Owen Power would move up to the first power-play unit.