Addai was selected in the first round (30th overall) of the 2006 NFL Draft by the Indianapolis Colts.
Addai was the third running back selected by the Colts in the first round since 1994, when they selected Marshall Faulk with the second overall pick in 1994 and Edgerrin James fourth overall in 1999.

On November 26, 2006, Addai tied a Colts franchise record for most rushing touchdowns in a game held by Lenny Moore, Lydell Mitchell and Eric Dickerson, as well as the NFL rookie record by rushing for 4 touchdowns against the Philadelphia Eagles.
He was named the NFLs "Offensive Rookie of the Month" for November on December 7, 2006.

During the 2006 season, Addai led all rookie running backs in rushing yards with 1,081.
He also became the first NFL running back to exceed 1,000 rushing yards without starting a regular-season game.
His first career start came on January 6, 2007, for the Colts/Chiefs wildcard playoff game.
During the game, he ran for 122 yards and a touchdown on 25 carries and caught seven passes for 26 yards.
For the next week, leading up to the divisional round of the playoffs, Addai became the target of Baltimore Ravens' linebackers Ray Lewis' and Bart Scott's trash talking, but did not respond to either of their comments, as the Colts upset the favored Ravens 15-6.
On January 21, 2007, in the AFC Championship Game against the New England Patriots, Addai scored the game-winning touchdown with 1:00 remaining, giving the Colts a victory and a trip to Super Bowl XLI.
The Colts went on to win the game with their rush attack.
Addai had 77 rushing yards and 10 receptions for 66 yards, for 143 total yards.
His 10 receptions were the most ever by a running back in a Super Bowl, which left him one catch short of the overall record.

On November 4, 2007, in a Week 9 game against the New England Patriots, Addai became the first Indianapolis Colt ever to gain 100 yards receiving and 100 yards rushing in one game.
Joseph was rewarded for his play in the 2007 season by being invited to his first and only Pro Bowl in January 2008.

On November 1, 2009, in a game against the San Francisco 49ers, Addai completed his first professional pass, a touchdown to Reggie Wayne.

Addai became an unrestricted free agent after the 2010 season and was re-signed by the Indianapolis Colts on July 31, 2011.
Addai had his worst season statistically in 2011 as he rushed for 433 yards and only one touchdown.
He was released following the 2011 season on March 9, 2012.
Addai was selected in the first round (30th overall) of the 2006 NFL Draft by the Indianapolis Colts. Addai was the third running back selected by the Colts in the first round since 1994, when they selected Marshall Faulk with the second overall pick in 1994 and Edgerrin James fourth overall in 1999.
On November 26, 2006, Addai tied a Colts franchise record for most rushing touchdowns in a game held by Lenny Moore, Lydell Mitchell and Eric Dickerson, as well as the NFL rookie record by rushing for 4 touchdowns against the Philadelphia Eagles. He was named the NFLs "Offensive Rookie of the Month" for November on December 7, 2006.
During the 2006 season, Addai led all rookie running backs in rushing yards with 1,081. He also became the first NFL running back to exceed 1,000 rushing yards without starting a regular-season game. His first career start came on January 6, 2007, for the Colts/Chiefs wildcard playoff game. During the game, he ran for 122 yards and a touchdown on 25 carries and caught seven passes for 26 yards. For the next week, leading up to the divisional round of the playoffs, Addai became the target of Baltimore Ravens' linebackers Ray Lewis' and Bart Scott's trash talking, but did not respond to either of their comments, as the Colts upset the favored Ravens 15-6. On January 21, 2007, in the AFC Championship Game against the New England Patriots, Addai scored the game-winning touchdown with 1:00 remaining, giving the Colts a victory and a trip to Super Bowl XLI. The Colts went on to win the game with their rush attack. Addai had 77 rushing yards and 10 receptions for 66 yards, for 143 total yards. His 10 receptions were the most ever by a running back in a Super Bowl, which left him one catch short of the overall record.
On November 4, 2007, in a Week 9 game against the New England Patriots, Addai became the first Indianapolis Colt ever to gain 100 yards receiving and 100 yards rushing in one game. Joseph was rewarded for his play in the 2007 season by being invited to his first and only Pro Bowl in January 2008.
On November 1, 2009, in a game against the San Francisco 49ers, Addai completed his first professional pass, a touchdown to Reggie Wayne.
Addai became an unrestricted free agent after the 2010 season and was re-signed by the Indianapolis Colts on July 31, 2011. Addai had his worst season statistically in 2011 as he rushed for 433 yards and only one touchdown. He was released following the 2011 season on March 9, 2012.
Joseph Addai