Chicago Bears Grasu was selected by the
Chicago Bears in the third round (71st pick overall) of the
2015 NFL draft. The move reunited him with college teammate
Kyle Long. On August 30, 2016, Grasu was placed on
injured reserve. On September 2, 2018, Grasu was released by the Bears.
Baltimore Ravens (first stint) On September 24, 2018, Grasu was signed by the
Baltimore Ravens. He played in three games before being released on November 24, 2018.
Miami Dolphins On December 12, 2018, Grasu was signed by the
Miami Dolphins, but was released nine days later.
Tennessee Titans On February 7, 2019, Grasu was signed by the
Tennessee Titans, reuniting with college teammate
Marcus Mariota. He was released on August 31, 2019. He was re-signed on September 10, 2019. He was released again on October 8, 2019. He was signed once again on October 31, 2019. He was released on December 3, 2019.
Baltimore Ravens (second stint) On December 4, 2019, Grasu was claimed off waivers by the Ravens.
San Francisco 49ers On August 20, 2020, Grasu signed with the
San Francisco 49ers. He was released on September 5, 2020, and signed to the
practice squad the next day. After being elevated to the active roster for the team's first two games, Grasu was promoted to the active roster on September 26, 2020. He was placed on the team's reserve/
COVID-19 list by the team on November 19, 2020, and activated on November 25. He was placed back on the COVID-19 list on December 28, 2020, and activated on January 14, 2021.
Las Vegas Raiders On October 25, 2021, Grasu was signed to the
Las Vegas Raiders practice squad. After the Raiders were eliminated in the
2021 Wild Card round of the playoffs, he signed a reserve/future contract on January 17, 2022. On August 30, 2022, Grasu was waived by the Raiders and signed to the practice squad the next day. He was promoted to the active roster on December 10. On August 29, 2023, Grasu was released by the Raiders and re-signed to the practice squad. He was signed to the active roster on December 21. ==Personal life==