I'm fine with saying 2016 is arguably Lester's best. There's some stuff in his batted ball data that suggests his batted ball luck wasn't all luck. Fantastic numbers for things like xBA and xwOBA. Really low exit velocity, particularly on fly balls, which also had more loft under them than usual. A low % of pitches barreled. Granted, he's been great in these facets every year -- even last year. And we have very few years of data on this stuff, so it's impossible to measure against his early Boston years. But, 2016 stands out as a great year for him in those areas. Also, for the years we have spin rate numbers, his spin rates on all his pitches were the highest in 2016 -- mostly by significant margins. So his stuff might have been a little more nasty and harder to square up. But, mainly I'm OK with saying it because he's basically been the same pitcher every year. 4-5 wins. 200-210 innings. Save for the mid-career hiccup when he lost the feel for his cutter for a couple years, he's mostly been the same guy for a long time. Velocity has been about the same. Movement on his stuff has been about the same. His repertoire and pitch mix have been about the same. It would be difficult for me to say definitively which is his best season when he has like 5 or 6 of them within a win of each other. 2014 seems like the best bet. He had his best periphs in the most innings. And he outpaced his periphs in ERA, too. But there are things in the periphs that might lie to us, too. Pitch framing. Just plain getting screwed with bad calls from umps behind the dish. Some variance in ball/strike order and swing/miss order leading to weird things. A few fluky home runs screwing things up. Within a win or so of difference, it's going to be awfully tough to strip away all luck and randomness, even if we can take away things like defense. So I think it's fine to look beyond the periphs for something else when it's that close. Regardless, UMFan's point stands. Lester is a year removed from being his normal self. Last year was ugly, and his age and injuries certainly aren't harbingers for success. But his main problem last year was with what happened when batters made contact with the ball. High HR/FB. High BABIP. Extremely low LOB%. He had an ERA larger than his FIP, which was larger than his xFIP. And as I said earlier, his batted ball numbers from last year contradict the notion that he was hit hard. Of 99 pitchers with at least 400 batted balls against them, Lester had the 18th lowest average exit velocity. Of pitchers that threw at least 2,500 pitches, his xWOBA was 22nd lowest. He also allowed the lowest Contact% of his career. I think he's a decent bet to bounce back, despite his age and injuries.