After another sterling start from Cole Hamels on Saturday, I thought it might be time to take a deeper dive into what’s made him so good so far this year. A 3.08 ERA with a 3.50 FIP isn’t dominating, but he’s right behind Lester and Quintana in the latter category. And if you were to remove his first start of the year, which really was just one bad inning, his ERA is 2.44 since. He hasn’t given up more than three earned in any start since, and he’s only done that once in the seven starts since that what-have-ya in Texas.

So what’s going on here?

The first thing that jump out about Hamels is the great increase in his ground-ball rate. It’s at 56%, which is 11 points higher than last year and the highest by four points of any mark in his career. It’s the third-highest in baseball among qualified starters. Surely there’s a reason that Hamels has decided to become Derek Lowe? Well for one, when you have the Cubs infield, ground-balls are a good idea (although at second they haven’t really managed to play anyone that much above “twit” level, as Bote has been just a tick below average there). But there’s been a change in approach as well.

The next thing anyone would notice about Hamels’s methods this year is there are a ton more four-seam fastballs. He’s throwing it half the time, up from 45% last year, at the expense of his cutter. has it at 41%, up from 30% last year. This was something we began to see last year, as upon arrival on the Northside the Cubs got him using his fastball way more, jumping from 29% in July before the trade to 41% and 44% the next two months. So it’s a continuing of that trend. And we did see a surge in grounders when Hamels first arrived, at 55%, but that went away in September last year.

Still, this doesn’t explain it all. Hamels is getting about the same percentage of grounders on that four-seam as he has his whole career. Obviously, throwing it more often means more grounders total (and you’re welcome for that math lesson). But it has to be more than that. And where he’s putting that fastball might be the answer.

Here’s where Hamels has thrown his four-seamer throughout his career:

And here’s what he’s doing this year so far:

So as you can see, he’s gone a bit Lester in that he’s just hammering the outside corner to righties. Which gets balls rolled over, or hitters stretching, and that’s how you get a lot of grounders. That idea has spread to his cutter as well, even though he’s using it less. Here’s where his career usage has gone and where he’s throwing it this year:

He still uses it to get inside on righties, just enough to keep them off the fastball outside, but hasn’t been shy about throwing it outside as he was either.

Perhaps more impressive than the ground-ball rate is that the amount of loud contact Hamels is giving up has fallen off a cliff. He’s only giving up a 16% line-drive rate, which is top-1o in baseball. His hard-contact rate has dropped from 41% last year to a much more manageable 33%, and even most of that hard-contact has still been on the ground.

The question is whether Hamels is benefitting too much from a .234 BABIP, which isn’t going to stick around much. But considering the soft and grounded nature of what he’s surrendering, and the Cubs plus-defense (5th best in ground-ball defensive efficiency), it also might not rise dramatically. The last time Hamels gave up anywhere near this many grounders, 2011 with Philly, he had a .255 BABIP, as Utley, Rollins, and Polanco gobbled everything up back when they were still young.

Stamina will be a question, as he’s 35 now and wasn’t as good in September of last year. And control has been an issue of late. But when you give up soft contact and most of it on the ground, good things tend to happen.