On August 31, 2019, Sims was waived by the Redskins and was signed to the team's practice squad the following day.[10][11] He was promoted to the active roster on October 2, 2019.[12] Sims was released by the team on October 19, 2019, but re-signed to the practice squad two days later.[13][14] He was signed to the active roster on November 16, 2019.[15]
He was waived by Washington on September 5, 2020, but signed with their practice squad the following day.[16][17] He was elevated to the active roster for the team's first two games of the season against the Philadelphia Eagles and Cardinals,[18][19] and was promoted to the active roster on September 22, 2020.[20]
Sims recorded his first career touchdown in a Week 6 game against the New York Giants in 2020.[21] Sims caught three passes for a career-high 110 yards in Week 9 against the Giants, the first 100-plus yard game of his career.[22] Sims had five receptions for 92 yards in a Week 13 win against the Pittsburgh Steelers.[23][24] Sims finished the 2020 regular season with 32 receptions for 477 yards and one receiving touchdown. Sims made his playoff debut in the Wild Card round against the Tampa Bay Buccaneers and was the team's leading receiver, catching seven passes for 104 yards.[25]
Washington placed a restricted free agent tender on Sims on March 16, 2021,[26] which he signed a week later.[27] In Week 11 of the 2021 season, he recorded his second career receiving touchdown in a 27–21 win over the Carolina Panthers.[28] In the Week 14 loss to the Dallas Cowboys, he had three receptions for 69 yards and a 43-yard touchdown from Taylor Heinicke.[29] On December 15, 2021, Sims was placed on the COVID-19 reserve list,[30] but was reactivated four days later. Sims re-signed a one-year deal with the team on March 17, 2022.[31]
Las Vegas Raiders
Sims signed a one-year contract with the Las Vegas Raiders on March 21, 2023.[32] He was released on August 29, 2023.[33]
New York Giants
On September 4, 2023, Sims signed with the Giants' practice squad.[34] He was released on October 10, 2023.[35]
Philadelphia Eagles
On November 30, 2023, Sims was signed to the Philadelphia Eagles practice squad.[36] On December 5, 2023, he was released.[37]
Carolina Panthers
On December 6, 2023, Sims was signed to the Panthers practice squad.[38] He signed a reserve/future contract on January 8, 2024.[39] He was placed on the reserve/PUP list on July 26, 2024 and released on August 6.[40]