According to ABC 13, Thomas made history back in 2015 after becoming the first female to be a full-time official for the NFL. She was also chosen as the first woman to officiate a college football bowl game. Now she's reached another milestone.
She'll work as part of referee Ron Torbert's crew as a down judge. But she stressed that her focus was on "being the best official I can be".
The 46-year-old's record-breaking achievement came Sunday when she took to the field at Gillette Stadium in Foxborough, Mass.to serve as down judge for the AFC Divisional Playoff game between the Los Angeles Chargers and the New England Patriots.
Additionally, replay official Terri Valentini, who was hired by the National Football League in 2017, has been assigned to Saturday afternoon's game between the Kansas City Chiefs and Indianapolis Colts at Arrowhead Stadium.
Though Thomas has been the only female referee in the league for much of her career, Jen Welter, the first female NFL assistant coach, said that when she was hired in 2015, she "started the dominos" for women in the league.
Last year, she was named as an alternate for the match-up between the Atlanta Falcons and the Los Angeles' Rams wild-card playoff game. "The guys don't think of me as a female, they see me as just another official".
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Boston and Miami didn't play each other in 2018 - the last meeting between the clubs, before Thursday , came on December 20, 2017. Leading up the Thursday's game against the Miami Heat , Celtics point guard Terry Rozier had circled January 10 on his calendar.