The two-time All-Star will likely compete with Kevin Plawecki for the backup catcher role behind starter Christian Vazquez. Red Sox interim manager Ron Roenicke knows Lucroy from their time together with the Milwaukee Brewers.
Lucroy underwent neck surgery early in the offseason and is said to be feeling "100% better," according to Jon Heyman of MLB Network.
The 33-year-old has posted a career .274/.335/.416 slash line with 108 home runs and 545 RBIs while playing for the Brewers, Texas Rangers, Colorado Rockies, Oakland Athletics, Los Angeles Angels, and Chicago Cubs.
Lucroy led the majors in doubles (53) in 2014. He was one of the best catchers in baseball from 2011-16, accumulating 25 WAR, according to FanGraphs.