Kelly's professional career started in 2005 with the Minnesota Swarm of the National Lacrosse League (NLL). He was also drafted in the Major League Lacrosse (MLL) supplemental draft that same year by the Los Angeles Riptide. Kelly was named L.A.’s “Newcomer of the Year” by US Lacrosse Magazine and lead L.A. to a #2 Ranking in face-off wins for the 2006 season. Anthony remained with the Riptide in 2007 and enjoyed a great year with 169 face offs won, a career high 62 ground balls, and 6 points. In 2008 Kelly won 184 faceoffs for the Riptide and was selected to participate in his first MLL All Star Game and skills competition. He won the fastest shot competition with a shot clocked at 109 mph (175.4 km/h).