Welch signed with the Baltimore Ravens as an undrafted free agent following the 2020 NFL draft on May 6, 2020.[2] He was waived during final roster cuts on September 5, 2020,[3] and re-signed to the team's practice squad the next day.[4] He was placed on the practice squad/injured list on September 15,[5] and activated back to the practice squad on October 6, 2020[6] He was elevated to the active roster on October 17, 2020, and October 31, 2020, for the team's weeks 6 and 8 games against the Philadelphia Eagles and Pittsburgh Steelers, and reverted to the practice squad after each game.[7][8] He was promoted to the active roster on November 7, 2020.[9]
The Ravens placed an exclusive-rights free agent tender on Welch on March 10, 2021.[10] He signed the one-year contract on April 18, 2021.[11]
On April 8, 2023, Welch re-signed with the Ravens.[13] He was released on August 29, 2023.[14]
Green Bay Packers
Welch was signed to the Green Bay Packers practice squad on August 31, 2023.[15] He was promoted to the active roster on September 28, 2023.[16] Welch was re-signed on March 14, 2024.[17] He was released on August 27, 2024.[18]
Denver Broncos
On August 29, 2024, Welch was signed by the Denver Broncos.[19] On October 15, he was released by the Broncos.[20]
Baltimore Ravens (second stint)
On October 16, 2024, Welch was signed to the Baltimore Ravens practice squad.[21] He was promoted to the active roster on November 23.[22]