In 1997, Maslowski signed as a rookie free agent with the San Diego Chargers, but was cut by the team prior to the start of the regular season. In 1998, he played in the Arena Football League for the San Jose Sabercats. In 1999, Maslowski signed a contract with the Kansas City Chiefs of the NFL. The Chief then allocated him to NFL Europe where he played one season for the Barcelona Dragons of NFL Europe in 1999 where he set the single season record for tackles with 105 tackles, breaking the previous record of 95 tackles set by Anthony Fieldings of the Rhein Fire. Maslowski is the only player in the history of the NFL Europe to record a 100 tackle season. As a member of the Dragons, Maslowski was twice named the NFL Europe Defensive Player of the Week, was the Defensive Player of the Year, and helped lead his team to play in World Bowl VII against the Frankfurt Galaxy.