In his career, Harrell had also played for the New England Sea Wolves, Toronto Phantoms, and Colorado Crush and Chicago Rush.
Harrell played two seasons at Florida State University (1995 and 1997), catching 36 career passes for 466 yards and four touchdowns, after transferring from City College of San Francisco.
He recorded 23 receptions for 288 yards as a senior in 1997 but tore ligaments in his right knee in the season finale against Florida and missed the Seminoles win over Ohio State in the 1998 Sugar Bowl.
He recorded seven passes for a season-high 145 yards and four touchdowns in an overtime loss to the Dragons on the final day of the season.
He finished the season ranked ninth in the league in receptions, eighth in receiving yards and fourth in scoring (234 points).
In 2004, Harrell was voted Second Team All-Arena after recording 114 receptions for 1,715 yards and 43 touchdowns in 16 games.
Harrell had 13 receptions for a career-high 208 yards and three touchdowns and was named Offensive Player of the Game on the road against the Detroit Fury.
In 2005, Harrell was named AFL Offensive Player of the Year and First Team All-Arena after recording 122 receptions for 1,486 yards and 41 touchdowns and helping lead Colorado to the ArenaBowl XIX championship.
He was named Offensive Player of the Game against the Los Angeles Avengers after recording 10 receptions for 135 yards and five touchdowns.
He was also named Offensive Player of the Game three other times during the season, on the road against the Arizona Rattlers, against the Gladiators and against the Nashville Kats.
In 2006, Harrell was named AFL Offensive Player of the Year and First Team All-Arena for the second-consecutive season after setting career highs with 152 receptions for 1,920 yards and a league record 60 touchdowns in 16 games.
He was named AFL Offensive Player of the Month for April after recording 56 receptions for 642 yards and 21 touchdowns in just five games.
In 2007, Harrell was voted Second Team All-Arena after recording 132 receptions for 1,547 yards and 47 touchdowns in 16 games.
He was named Offensive Player of the Game for the third time, against the Gladiators after recording nine receptions for 91 yards and four touchdowns.
Harrell was named Offensive Player of the Game after recording eight receptions for 95 yards and three touchdowns in a season-opening loss to the Grand Rapids Rampage.