8 IP, 3 ER is just ok for Lester. I was happy with his outing because of how he's thrown this year, but if it was Buchholz out there that allowed 3 earnies over 8 IP, I would be much more "meh" over it.
Lester has not been a good SP by any means this year, but it's also been exacerbated by the fact that he actually is getting unlucky via his BABIP (.324) and his strand rate (63.8%). I'm not sure if he can do anything to correct these problems, or if they will just normalize over time. I do know, though, that the 3rd run that was scored last night was on a change up about 4 feet outside that Doumit likely didn't see because he looked like he was flailing at a pinata with his eyes closed.
Still, though, there's no excuse to not beat the Twins who are throwing a journeyman at you.