The 29-year-old left-handed hitter appeared in 161 games for Boston from 2022-24 and batted .264 with a .315 on-base percentage, .370 slugging percentage, seven homers, 20 doubles, two triples, 46 RBIs and 38 runs (472 plate appearances).
The Red Sox designated McGuire for assignment last July 28 after they acquired catcher Danny Jansen from the Blue Jays. McGuire cleared waivers and was outrighted to Triple-A Worcester where he spent the remainder of the 2024 season.
He elected to become a free agent Sept. 30.
He played in 11 games in the Dominican Winter League this offseason, going 10-for-29 (.345) with a .441 on-base percentage and no extra-base hits.