He was the starting quarterback while playing college football for the Virginia Tech Hokies in the early 2010s, where he finished as the school's all-time leader in passing yards and touchdowns before being selected by the Arizona Cardinals in the fourth round of the 2014 NFL draft.

He switched to tight end, a position he last played in high school, with the Detroit Lions in 2016 and continued the role with the Buffalo Bills and Washington Football Team / Commanders.

[1] He played quarterback, wide receiver, tight end, and defensive back for the Bees' football team.

[13] Thomas was the sixth quarterback taken in the draft behind Blake Bortles (3rd, Jacksonville Jaguars), Johnny Manziel (22nd, Cleveland Browns), Teddy Bridgewater (32nd, Minnesota Vikings), Derek Carr (36th, Oakland Raiders), and Jimmy Garoppolo (62nd, New England Patriots).

[15] Thomas made his NFL debut against the Denver Broncos on October 5 in relief of concussed starter Drew Stanton.

After Week 16 and after the Cardinals' one-sided loss to the Seattle Seahawks, head coach Bruce Arians announced that rookie Thomas would start over struggling Ryan Lindley in the regular season finale against division rival San Francisco 49ers, but "promised to have a quick hook.

[28] Thomas was on and off the Giants' practice squad throughout the first three months of the season, before being released on November 22; he had a total of 13 transactions with the team.

[32] He gained significant playing time in 2017 after fellow tight end Charles Clay was sidelined with a knee injury.

On October 22, 2017, he caught his first NFL touchdown, a 22-yard pass from former Virginia Tech teammate Tyrod Taylor, in a home win against the Tampa Bay Buccaneers.

[34] He also completed his first pass attempt since his time as a quarterback in Arizona, connecting with wide receiver Robert Foster for 16 yards on a fake punt play for a first down.

[48] On December 8, he was placed on injured reserve for a second time after suffering a knee injury via a low block from Las Vegas Raiders' defensive end Yannick Ngakoue three days earlier.

[54] In 2023, in a Week 2 win over the Denver Broncos, Thomas left the game with a concussion after scoring a touchdown and receiving an illegal helmet-to-helmet hit from safety Kareem Jackson.

Thomas finished the season with 55 receptions for 496 yards and four touchdowns (as well as a 2-point conversion in a loss to the Miami Dolphins) and 2 lost fumbles over 16 games with 15 starts.