After going undrafted in the 2015 NFL Draft, Rawls signed with the Seattle Seahawks on May 2, 2015.
He was behind Robert Turbin and Christine Michael on the depth chart, but after the Seahawks traded Michael to the Dallas Cowboys and Turbin suffered an injury and was subsequently waived from the team, Rawls made his way onto the roster.
He began as a backup along with Fred Jackson to starter Marshawn Lynch and saw his first game action in the season opener for Seattle against the St. Louis Rams.
Lynch underwent surgery later in the season, moving Rawls to a starting role.

On September 27, 2015, Rawls saw his first meaningful playing time in a game, rushing for 104 yards in relief of an injured Lynch.
It was the first time any Seattle running back beside Lynch had gained 100 yards since 2012.

Continuing to fill-in for the injured Lynch, Rawls rushed for 169 yards on October 11, 2015, including a 69-yard touchdown run in a game against the undefeated Cincinnati Bengals.
However, the Seahawks would give up a 17-point fourth quarter lead to lose the game, curiously not using Rawls once during overtime.

With Lynch again sidelined with an abdomen injury, Rawls started his third career game, this time against the Seahawks' division rival San Francisco 49ers, on November 22, 2015.
He ran for 209 yards on 30 carries and had 255 total yards and 2 touchdowns,  the first time a Seahawk eclipsed 200 rushing yards since former NFL MVP Shaun Alexander in 2006.
At this point in the season, Rawls had run for three 100-yard games, while incumbent starter Marshawn Lynch had run for over 75 yards only once.

On November 22, 2015, Rawls broke the Seahawks franchise rookie-record for rushing yards (209).
Rawls also made NFL history as the first player with 250-plus scrimmage yards, a rushing touchdown and a receiving touchdown in the same game.
Rawls continued his breakout campaign with touchdowns against the Steelers and Vikings in Weeks 12 and 13, respectively.
With the performance vs the Vikings earning Rawls the Pepsi NFL Rookie of the Week honors.

On December 13, 2015, Rawls' successful rookie season was cut short after suffering a fractured ankle on the Seahawks opening drive against the Baltimore Ravens that forced Rawls to be out for the season.
Rawls had 6 carries for 44 yards before he was injured.
Rawls had 147 carries for 830 yards and 4 rushing touchdowns and 1 receiving touchdown in his successful rookie season.
On December 15, 2015, Rawls was placed on Injured Reserve.
He was voted to be in the PFWA All-Rookie Team (2015).
After going undrafted in the 2015 NFL Draft, Rawls signed with the Seattle Seahawks on May 2, 2015. He was behind Robert Turbin and Christine Michael on the depth chart, but after the Seahawks traded Michael to the Dallas Cowboys and Turbin suffered an injury and was subsequently waived from the team, Rawls made his way onto the roster. He began as a backup along with Fred Jackson to starter Marshawn Lynch and saw his first game action in the season opener for Seattle against the St. Louis Rams. Lynch underwent surgery later in the season, moving Rawls to a starting role.
On September 27, 2015, Rawls saw his first meaningful playing time in a game, rushing for 104 yards in relief of an injured Lynch. It was the first time any Seattle running back beside Lynch had gained 100 yards since 2012.
Continuing to fill-in for the injured Lynch, Rawls rushed for 169 yards on October 11, 2015, including a 69-yard touchdown run in a game against the undefeated Cincinnati Bengals. However, the Seahawks would give up a 17-point fourth quarter lead to lose the game, curiously not using Rawls once during overtime.
With Lynch again sidelined with an abdomen injury, Rawls started his third career game, this time against the Seahawks' division rival San Francisco 49ers, on November 22, 2015. He ran for 209 yards on 30 carries and had 255 total yards and 2 touchdowns,  the first time a Seahawk eclipsed 200 rushing yards since former NFL MVP Shaun Alexander in 2006. At this point in the season, Rawls had run for three 100-yard games, while incumbent starter Marshawn Lynch had run for over 75 yards only once.
On November 22, 2015, Rawls broke the Seahawks franchise rookie-record for rushing yards (209). Rawls also made NFL history as the first player with 250-plus scrimmage yards, a rushing touchdown and a receiving touchdown in the same game. Rawls continued his breakout campaign with touchdowns against the Steelers and Vikings in Weeks 12 and 13, respectively. With the performance vs the Vikings earning Rawls the Pepsi NFL Rookie of the Week honors.
On December 13, 2015, Rawls' successful rookie season was cut short after suffering a fractured ankle on the Seahawks opening drive against the Baltimore Ravens that forced Rawls to be out for the season. Rawls had 6 carries for 44 yards before he was injured. Rawls had 147 carries for 830 yards and 4 rushing touchdowns and 1 receiving touchdown in his successful rookie season. On December 15, 2015, Rawls was placed on Injured Reserve. He was voted to be in the PFWA All-Rookie Team (2015).
Thomas Rawls