In 2003, Maslowski's season, and ultimately his career, were cut short by recurrent knee injuries which he first sustained in 2001. His MCL and PCL were completely torn from bone on his left leg and he underwent a tibial osteotomy which is designed to correct the alignment of the knee. He was only the second professional athlete to attempt a return to playing after undergoing such a surgery, the other was Steve Yzerman of the Detroit Red Wings. During training camp in the 2004 season, Maslowski attempted to make a comeback, but his left knee was not at full strength and the Chiefs placed him on the injured reserve. Again in 2005, he attempted a comeback, but decided to retire because he was not achieving his full potential.