Per ESPN's Jeff Passan on Saturday, the Red Sox have agreed to a one-year, $10 million deal with the 32-year-old right-hander.
Starting pitching was a significant problem for the Red Sox in 2020. Chris Sale missed the entire season after undergoing Tommy John surgery in March.
With their best pitcher unavailable, the Red Sox pieced together a rotation that included Nathan Eovaldi, Martin Perez, Chris Mazza, Zack Godley and Ryan Weber.
Boston's starters ranked last in Major League Baseball in FanGraphs wins above replacement (0.5), 29th in innings pitched (246) and 25th in ERA (5.34).
Richards is coming off a solid season for the San Diego Padres. He had a 4.03 ERA with 46 strikeouts in 51.1 innings over 14 appearances. Injuries have limited him to a total of 198.2 innings over the past five seasons combined.
If the Red Sox are getting the 2020 version of Richards, he will be a bargain for a team that desperately needs all the pitching it can get. If Boston can add a healthy Sale to the mix as well, it could be an under-the-radar playoff contender in the American League.