Denver Broncos Sizer signed with the
Denver Broncos as an undrafted free agent on May 13, 2019. He was waived on July 26, 2019, but was re-signed on August 4. He was waived on August 31, 2019, and re-signed to the practice squad. He was promoted to the active roster on December 14, 2019. On April 27, 2020, Sizer was waived by the Broncos. He was re-signed to their practice squad on September 24, 2020. He signed a reserve/future contract on January 4, 2021. On August 17, 2021, Sizer was waived by the Broncos. He was re-signed to the practice squad on December 28. He was released on January 3, 2022.
New Jersey Generals Sizer signed with the
New Jersey Generals of the
United States Football League on April 1, 2022. He was transferred to the team's inactive roster on April 30 due to a chest injury. He was moved back to the active roster on May 6. Sizer was placed on the injured reserve list by the team on May 4, 2023. He was transferred to the inactive list on June 8. Sizer became a free agent after the 2023 season.
Ottawa Redblacks On January 22, 2024, Sizer signed with the
Ottawa Redblacks of the
Canadian Football League (CFL). He was released on May 11, 2024. ==References==