Clemens vying for eighth Cy Young
Clemens was obviously the best pitcher in the American League from 1986 through 1992 and then again in 1997 and 1998. He was brilliant in 1994 and 1996, too. So it's not easy to pick Clemens' greatest season; after all, he's won seven Cy Young Awards, and while he didn't deserve all seven of them, there were a couple of times he didn't win but probably should have.
The competition, I think, comes down to two seasons: 1990 and 1997. In 1990, Clemens went 21-6 with a 1.93 ERA (league average: 4.07). In 1997, he went 21-7 with a 2.05 ERA (league average: 4.62). These are the only two seasons in Clemens' career in which his ERA was less than half the league average. His next best season in that regard was 1994, when the players' strike limited him to 24 starts (and his ERA was 56 percent of the league average).