Maslowski joined the Chiefs in 1999, after the conclusion of the 1999 NFL Europe season, and played a significant role of the Chiefs special teams, earning the Chiefs' prestigious Mack Lee Hill Award, which is awarded to the most outstanding rookie of the team. His 2001 season was plagued by two major knee injuries, tearing his MCL and PCL in his left knee, but in the 2002 season he earned a spot at linebacker. In the 2002 season, Maslowski recorded 162 tackles, 109 of which were solo tackles, and broke the Chiefs single season record in tackles, which had previously been 157 tackles set by linebacker Gary Spani in 1979. Maslowski's single season tackle record for the Chiefs still stands today.