Why is Todd Frazier having such a good year?

With a guy like Billy Hamilton on first base, you’re likely to get a fastball. That’s a good thing for Todd Frazier, who has traditionally feasted on fastballs. But does Billy Hamilton also make for a distraction at first base? Someone taking off for second base in your peripheral vision doesn’t make for great concentration at least.

That distractive property of a speedster at first base was the possible explanation that Ben Lindbergh had for the decreased production batters saw when they were at the plate and an aggressive runner was on first.

But ask Frazier about it and he says he’s "locked in" at the plate. "When they throw over three or four times, it’s not a distraction, it makes me feel a little better knowing they’re worried about him and not me," the Reds third baseman said. "He understands what he’s doing and I understand what I’m doing."

There’s a difference between the runner just being at first base and taking off, though. Both Joey Votto and Todd Frazier agreed that they always take when Hamilton takes off from first. Of the 34 times that Hamilton has taken off for a new base with one of those two at the plate, the batter has swung six times. Considering that Votto’s swung at nearly 40% of the pitches he’s seen over that time frame, and Frazier’s swung at nearly 50%, a 17.6% swing rate probably qualifies as ‘never swinging.’

So these two batters generally take when Hamilton is running, and only 12 of the 28 times they took did that pitch turn into a strike. Only six times was that pitch strike two, and only once did the pitch strike the batter out. So it’s not as if Hamilton’s actual stolen bases have put Votto and Frazier in bad positions when seen as a whole.

And Hamilton has given them the opportunity to see more fastballs. "There’s a predictable fastball that I’m going to get," said Votto. The Reds’ first baseman was seeing more fastballs than he’d ever seen this year before he hit the disabled list (60.5% this year, 56.6% career).

Frazier has only seen a slight uptick (56.2% this year, 56.0% last year), but he likes fastballs — "That’s what I hit and that’s why I like to hit" he said of the pitch. It at least seems possible some of his breakout this year has been fueled by fastballs with Hamilton on base.

The two can, indeed, owe some of their added fastballs to Hamilton. When Hamilton is on base in front of them, they’ve seen a fastball 57% of the time. For those two hitters, that’s above their career fastball percentages. But it’s not actually a ton more fastballs than the rest of the league would see. The average National League starter throws a fastball… 57.6% of the time.

Still, for our two Reds hitters, they’re seeing more fastballs, which is good, right? Even if you take out the instances where Hamilton is running and they’re not swinging, they’re getting 55% fastballs this year.

But what if they’re taking a little more often in case Hamilton wants to go. Maybe they see a flinch and think he is going? Listen to Frazier and you hear that, yes, perhaps they’re taking a bit more even when Hamilton is not stealing: "If I need to take a couple pitches, get to two strikes, I’m not afraid to hit with two strikes."

With Billy Hamilton on first or second (and not engaged in stealing a base), Frazier has swung at 50.6% of the balls in he’s seen. He’s swung at 52.6% of the balls he’s seen this year in general. If he’d swung three more times with Hamilton in a position to steal, these numbers would be exactly the same.

What happens when Frazier does swing at a pitch with Hamilton on base? Could some of the added bonus of having a speedster on base in front of him actually come from balls in play? Infield defenders have to stay close to bags to try to keep Hamilton from stealing, is that opening holes for Frazier?

Frazier has swung 87 times with Billy Hamilton in stealing position since the young man was called up last year. He’s made contact 73.8% of the time, which is worse than his yearly rate (75.2%). Of the balls he’s put into play, 37.5% have found grass. 32.7% of his balls in play this year have been hits in general. Still, the difference between these two numbers is two hits.

Todd Frazier is having a great year. He probably owes a few hits and a few fastballs to Billy Hamilton. But maybe it’s really more about other factors. He credits hitting coach Don Long with "helping me understand my swing," making a few tweaks and finding a good routine.

He’s been working on his pitch selection, that’s "always big" for the Reds’ third baseman. You can see that he’s swinging less at low pitches off the plate. Look at his swing heat map for 2013 on the top and 2014 on the bottom:

It’s nice to have Billy Hamilton on base in front of you, but it’s not the main driver of Todd Frazier’s good year. That would be Todd Frazier himself.

Thanks to Jake Sundstrom for collecting some of the data seen here.

Eno Sarris is an author at FanGraphs.