In 2016 Walker and Persinger left Roth's team to join Jamie Sinclair as the front end of a new team, with Alex Carlson as third. This new team found success, winning the 2017 U.S. Championships, but missed out on going to the World Championship due to not having enough points on the World Curling Tour. Walker and Team Sinclair competed for the winning Team North America at the 2017 Continental Cup of Curling. The team played in one Grand Slam, the 2017 Humpty's Champions Cup (qualifying as US champions), where they made it all the way to the quarterfinals.
The United States Curling Association would change the high performance teams the following season, for the next Olympic quadrennial. Walker remained at lead for skip Sinclair, with twin sisters Sarah and Taylor Anderson playing third and second respectively. The team did not have a very successful season, up until the 2019 United States Women's Curling Championship where they earned a third national title in a row, defeating Team Roth in the final. At the 2019 World Women's Curling Championship the team went 6–6 finishing in seventh place, just missing the playoffs. At the end of the season Walker announced she would be retiring from competitive curling.
Walker's retirement from competitive women's curling only lasted one season, as during the 2020 off-season Sinclair formed a new team, bringing Walker out of her short retirement to play at third, and adding two younger curlers for the front end, Cora Farrell and Elizabeth Cousins.[4][5] The team was not able to compete in any tour events due to the COVID-19 pandemic, but they were able to play in the 2021 United States Women's Curling Championship, held May 26–30 in Wausau, Wisconsin.[6] There, they topped the round robin with an undefeated 6–0 record, which qualified them directly to the championship final where they faced Team Cory Christensen.[7] After trailing early, Team Sinclair tied the game in the eighth end, but couldn't hold on for the win as Christensen scored two points in the extra end to win 8–6.[8]
Walker is a native of the Boston area. She is the daughter of two Scottish parents - Phil and Hilary Walker and has 2 younger sisters - Jillian and Emily. Monica is a huge Boston Bruins fan and enjoys playing soccer in her free time. She attended Boston University for her undergrad and completed a study abroad at the University of Edinburgh. [14]Walker attended the Simmons School of Management for an MBA and works in Quality Control in the Pharmaceutical industry. She lives in Brighton, MA and curls with Broomstones Curling Club[2]