Why bad results with a good card

Dick Drago as a 5th starter in my first season here. I won 100+ games and will probably never do it again. I didn't even know it was a mystery league until quite a way in. In any event, if I had know it was a mystery league, I might well have thrown Drago (though his run support provided 18 wins). He ended up with a 4.91 era and a 1.49 whip. Come to find out that I have his 1970 card: 3.75 era, 1.30 whip.
How does this happen? Is KC a pitcher's park? The rolls don't explain it. More pitchers rolls than batters. FX stats were not good for him: 31 63 9 17 Does that explain it? I am wondering whether I am missing something basic.

In standard leagues, both pitchers and hitters tend to underperform their cards. This is because, at least in the mystery format, leagues tend to be kind of all-star leagues with an over-representation of good players or good years. For example, in our leagues, a pitcher will face Mike Schmidt and George Brett more often than in real baseball - so you can imagine their numbers will be worse than in real baseball. If you play in a 60 mil league, your pitchers will perform better and more like the stats they got in real life.

Damn. Dick Drago won 18 games? Unless I'm playing in the Astrodome I expect my pitchers ERA to be 1.25-1.5 runs higher than their actual stats.