Many people think that McGriff’s numbers are, like many other recent hitters, a product of a hitter-friendly context. However, when one looks at McGriff’s entire career, we see that he split his time between a hitters’ era and a pitchers’ era, and overall his career context is about neutral.
McGriff's career is split about 60/40 between a hitters' era and a pitchers era - almost 4,000 of his plate appearances came in years that were pitcher-friendly (1988-93) and almost 6,000 PA in years that were more hitter-friendly (1987, 1994-2004). The result is a career where his overall context came out quite average. Baseball-reference.com has a feature whereby you can neutralize a player's stats, adjusting them to a neutral hitting environment (neutral era, neutral ballpark). Doing this for McGriff gives a neutralized career line of 288/377/511 - almost identical to his actual career line of 287/377/509. This is important, because many of today's players are being held to higher offensive standards for Hall election, because of a perception of the hitter-friendliness of this era. McGriff's career should be judged not against a steroid-era baseline, but against a historically neutral baseline.
More importantly, McGriff's peak came from 1988-94, and for several of those years offense was very low. From 1988 to 1992 the average offense in the majors ranged from 4.12 runs per game to 4.31. Teams in the National League in 1992 averaged only 3.88 runs per game - fewer than the NL average from 1963-66, when pitchers dominated. The National League slugged only 368 in 1992 - 13 points worse than the worst team in the majors in 2009, and 50 points below the MLB average in 2009.
This was an era when hitting home runs was considerably harder than it is today. Thus, although McGriff led both leagues in home runs, he did so at times when one could do so with 35-36 home runs. Considering this context, his peak looks like this:
In 1994 the hitters' era began, and McGriff was fourth out of 6 players to break 30 HR in only 113 games; he was fifth in the league and one of five players to break the 1000 OPS mark.
So, McGriff had an exceptionally strong peak. But, he also hit well after his peak. For eight more years after his peak McGriff averaged 150 games a year with a line of 288/371/489 with an average of 27 HR and 99 RBI a season. No, he wasn't matching the numbers of guys like McGwire and Bonds and Sosa, but he was still an effective hitter, with an OPS (adjusted for ballparks) 21% better than league average.
On to McGriff's similar players...