Tom Brunansky was acquired early in the 1990 season in a somewhat unfortunate trade. Despite having Lee Smith as a closer, Boston made the somewhat baffling decision to also sign Jeff Reardon as a free agent prior to the season. Predictably this caused a little bit of friction, and despite the fact that Smith was having a better season early on, he was traded to St. Louis for Brunansky.
Brunansky had hit 20 home runs for eight consecutive seasons coming into the 1990 season, but he would never hit 20 home runs again. Smith would have a terrific season in 1990 and finish second in the Cy Young vote in 1991. Brunansky was decent enough in 1990, but not the power hitter Boston thought they were getting. He hit .267/.342/.438 with just 15 home runs and 71 RBIs. He did make a terrific catch in the final game of the 1990 season which clinched the division title though, so there is that.
Brunansky's average tumbled in 1991, but hit 16 home runs. 1992 was his last season with Boston in his first stint and he was the the best hitter on the team that season, hitting .266/.354/.445 and lead the team with 15 home runs and 74 RBIs. He left after the season as a free agent and signed with Milwaukee.
In 1994, Brunansky was again acquired by the Red Sox in a trade, this time for Dave Valle. Brunansky hit 10 home runs in 48 games for Boston in his final season.