I dont care if its Kershaw 60 pitches into a perfect game.. i have zero problems starting Rondon in the 8th and flippin to Chapman in every close game we have a lead. Well, that's just silly. As you just saw with Chapman, those guys aren't perfect either. Arrieta was rolling. The first at bat, he was all over the corner of the zone and couldn't get a call. He wasn't really missing his spots or anything. The second AB was bad. And, of course, it was obvious to pull him there. But, before that, it is a lot of people looking at things in hindsight. Or, at best, it is people making a decision (Arrieta or the pen) that isn't entirely clear. Hell, people were calling for Chapman from the get-go over Rondon, and we saw how Rondon vs. Chapman worked out later in the inning. And those people weren't necessarily wrong. The point being: It's a tough call. And leaving in your ace when he is rolling isn't such a bad idea.