Los Angeles Rams After going undrafted in the
2016 NFL draft, Grigsby signed with the
Los Angeles Rams on May 4, 2016. On September 9, 2016, he was waived. Grigsby was signed to the Rams'
practice squad on September 12, 2016. On November 22, 2016, he was promoted from the practice squad to the active roster. On September 3, 2017, Grigsby was waived by the Rams.
Baltimore Ravens (first stint) On September 19, 2017, Grigsby was signed to the
Baltimore Ravens' practice squad.
New England Patriots On November 28, 2017, Grigsby was signed by the
New England Patriots off the Ravens' practice squad. He appeared in 5 games and had 5
tackles. Grigsby and the Patriots made it to
Super Bowl LII, but the Patriots lost 41–33 to the
Philadelphia Eagles. On November 13, 2018, the Patriots released Grigsby.
Detroit Lions On November 17, 2018, Grigsby was signed to the
Detroit Lions practice squad. He was promoted to the active roster on November 26, 2018. On February 15, 2019, Grigsby was released by the Lions.
Baltimore Ravens (second stint) On July 31, 2019, Grigsby was signed by the Ravens. He was waived on August 24, 2019.
Green Bay Packers On August 25, 2019, Grigsby was claimed off waivers by the
Green Bay Packers, but was waived the next day after failing his physical.
St. Louis Battlehawks In October 2019, Grigsby was selected by the
St. Louis Battlehawks of the
XFL in the
2020 XFL draft. He was waived on January 8, 2020.
Ottawa Redblacks Grigsby signed with the
Ottawa Redblacks of the
Canadian Football League on January 6, 2021. He was released on June 24, 2021. ==References==