I suppose that some of us will have difficulty recalling this one, but I don't think I can recall any Sox acquisition, save perhaps that of Manny Ramirez, who got the citizenry as pumped up as when the Sox signed Ken Harrelson.
I was about 16, and the Hawk was let go from the As by Charlie Finley in one of his bizarre moments. The Sox were able to sign him in what was one of those pre-free agency signings that didn't happen in those times. He had had about an .830 or so OPS with KC to that point, and had a big reputation as a slugger. Teenage fan that I was, I was convinced that he would turn the fortunes of the already-rallying Sox in the last month of the season. Psyched up, I was.
Why was it big? Well, back then there were no free agents; there was no comparable situation to compare it to, so it was sort of like adding this big, exciting power hitter to a team that would lose its other star in Tony Conigliaro. In fact, it's really hard to convey to younger Nationers how big that signing was.
Of course, while the Hawk had an excellent 1968, his performance for the Sox in '67 when they needed him was pretty poor, and one might think that, had he hit in the last month, the pennant race might have not been as ridiculously close as it was, and the Series (he went 1 for 13) might also have gone the other way. Then again, no one was hitting Gibson that Series.
By the time I actually got to New England, for college in the fall of 1969, Harrelson was gone off to the Indians, leaving only his sandwich shop on Mass. Ave. at Beacon St., a couple blocks from my fraternity house on Bay State Rd., meaning that even now I'm still partially composed of Hawk Bombs. He gone!