Okay, I kind of broke my rule here. Deron Johnson was actually with the Red Sox for parts of three seasons, but he did not come close to even a half season in any of the three seasons in which he appeared for the Red Sox. In fact, he only played in 29 games with the Red Sox over the course of those three seasons.
Johnson came up with the Yankees in 1960 and was traded to the Kansas City Athletics in 1961. After a year back in the minors in 1963, Johnson caught on with the Cincinnati Reds and emerged as a legitimate power threat, hitting 21 home runs in 1964. He followed that up with his best season, coming in fourth in the MVP vote when he hit .287/.340/.515 with 32 home runs and a league-leading 130 RBIs. Johnson played a couple more years with the Reds then started to bounce around afterwards, playing with the Braves, Phillies, Athletics, and Brewers over the next several seasons. He continued to show off some power, hitting 20 or more home runs six times. He hit 245 home runs in his career. He received MVP votes in three seasons.
In 1974, Johnson started the season with the Athletics, but struggled and was traded to the Brewers. He did not do much better with Milwaukee and the Red Sox purchased him in September. He played in 11 games for Boston, hitting .120/.115/.120 (how that is possible, I have yet to figure out). He was released at the end of the season and signed on with the White Sox for the 1975 season. He turned in a very good power season for Chicago, then was traded back to Boston in September again to help provide power in the absence of Jim Rice. He appeared in just three games, but hit .600/.667/.900 with his final home run and three RBIs. He came back to Boston in 1976, but appeared in just 15 games and hit .132/.233/.211, but he hit his final double and triple. He was released in June and did not appear in the Majors again. Johnson appeared at DH and first base while with the Red Sox.