Sometimes, offseason acquisitions work out. Sometimes they don't. Sometimes, they are spectacular failures.
It's hard to imagine quite what the thinking was. Matt Young was never really a great pitcher, or even a good one. Only once did he ever win more games than he lost, although he did pitch for mostly dreadful Seattle teams in the 1980's. Still, Young had three seasons where he lost 15, 19, and 18 games. His ERA was never great, but it was decent in three seasons. He was also extremely wild, walking 107 batters the year before he joined Boston.
But for some reason, Boston signed Matt Young in December of 1990, coming off a year in which he gave 107 walks, lost 18 games, but managed a 3.51 ERA and 176 strikeouts. The results were ugly. Young was injured a lot. He pitched in only 19 games in 1991, going 3-7 with a 5.18 ERA and 53 walks in 88.2 innings with 69 strikeouts. He also proved to be an absolutely atrocious fielder.
The next year, Young only started eight games but pitched out of the bullpen for 20 more. His ERA decreased to 4.58 but his walk rate and strikeout rate stayed roughly the same. He finished the season 0-4. However, he really topped himself on April 12, 1992 when he pitched a no-hitter against Cleveland, AND LOST THE GAME because of seven walks and four stolen bases allowed.
Young was released by the Red Sox in Spring Training of 1993 but showed up in Cleveland where he was again terrible. He was released and picked up by the Blue Jays who never used him in a Major League game and Young retired at the end of the season.