The more I play, the more nervous I am about having lefties in my rotation. And from reading the forum, I know I'm not alone. I think Paul8210 summed it up pretty well... It's just too easy for your opponents to build a lineup that crushes LHPs.
Also... pay attention to salaries and the stripe key, not to Cy Young awards. You can call Lollar a lesser pitcher, but he costs more than Carlton, and he should be expected to out-pitch him.
Why Lollar got a better card, I don't know (there are lots of factors involved in creating the cards, such as their real-world opponents that year, and so forth)... And why he isn't getting clobbered by right-handed hitters in your league, I also don't know... sometimes that
is just the way it goes.