 On March 14, 2015 Kowalski broke his collarbone after an accidental collision between him and Former-NHl'er Kevin Westgarth who was playing with the Belfast Giants during the 2014–2015 Season.Kowalski was ruled out for the rest of the season due to this injury.On May 21, 2015 Nottingham Panthers announced that Kowalski wouldn't be returning for the 2015–16 Season, ending a superb 5-year stint with the club.