You have to look past the raw runs-allowed numbers. If you do, though, you’ll quickly realize that a large part of the Rockies’ success this year has been their bullpen. Second in the National League in Wins Above Replacement, second in the entire league in Win Probability Added, third in Shutdowns, third from the bottom in Meltdowns, and first overall in Clutch: this is a strong unit. Talk to a some of Colorado’s relievers about what they’ve discovered this year and a trend emerges. There’s a bit of a secret, maybe, to building a good bullpen when you’re up a mile high.

At the center of everything seems to be Chris Rusin. “Rusin can throw two innings, he can throw three or four, but he can also pitch in one-run ballgames, and that’s huge,” said teammate Jake McGee. Others praised his consistency. Were the season to end today, Rusin would become only the 14th qualified reliever in the history of the Rockies to put up a sub-3.00 ERA.

Rusin’s step forward this season — and strong raw numbers despite Coors Field’s hostile run environment — might be a product of two developments. For one, he’s featured an increasingly balanced repertoire. Throwing the changeup more than ever, Rusin now utilizes his three main pitches (two-seamer, cutter, change) with similar frequency.

More impressive, perhaps, might be the movement he’s generated on his two-seamer at home. Fewer pitchers throw the sinker in Coors because it generally gets less movement in the thinner air. “It took me a while to figure out how to throw my two-seamer there,” Rusin admitted. “I just try to throw it more over the top.”

You can get a sense of his home games just by tracking the release points on his sinker:



Almost all the peaks occur at Coors. The corresponding horizontal movement on the sinker is almost as much a roller coaster:

But that doesn’t concern the lefty. “You don’t see the movement as a pitcher, but you judge that it’s moving by the contact the hitter makes,” Rusin said. “You gotta trust it, that’s it’s going to move a little bit. Even if you can’t see it, the hitters can’t see it much.” Even though he cedes over two inches of fade on the two-seamer at home, Rusin has gotten more ground balls on the pitch at home than he has away.

Jake McGee has also discovered a way to make his fastballs work for him despite Coors’s unique constraints — which is good, because nobody throws the fastball more often.

It’s technically only one fastball, but it behaves a bit differently under different circumstances. “When I throw it in to righties, it bears in on them, almost cuts in on them, and when I throw it away and up, it carries up and away,” the lefty pointed out. “I throw [it to] each side of the plate and it never leaks in.”

You can see it a bit here, almost cutting and definitely exploding:

When he throws it away — here, low and away — it does look like it has a bit of fade that keeps it from the heart of the plate:

“It’s my natural mechanics,” McGee said with a shrug. “I can change my angle a little bit, too.”

Improved health in his knee has helped him push off better, and McGee has added a quirk to his workout routine to better maintain that health. “The biggest thing I learned this year was to do your squats and heavy lifting. You don’t want to do those your first day back at home in Denver because it might take you four or five days to fully recover, so you do it one of the last few days in Denver, so you get out of town and it’s a little easier to recover,” McGee said.

When the lefty has had to take a step back — this month has been a little rough — there’s been someone for him there. “We have so many guys who have stepped up,” said former closer Adam Ottavino. “At every point in the season, somebody has been stepping up.”

Of course, that’s been a huge part of why the Rockies pen has been so good this year — and actually pretty good for a while now: it’s a focus for the team. They invest in it, and they try to have many options down there.

The club signed Greg Holland this offseason, despite having received a strong campaign at the closer spot from a returning Adam Ottavino the year before. They traded for Pat Neshek despite having a strong pen at midpoint this season. They’ve traded for Jake McGee at a decent cost — Corey Dickerson has been good for the Rays this season — and they paid Mike Dunn $19 million for three years. They’ve moved starters in and out of that pen, too.

There’s no real line to connect between Pat Neshek and Jake McGee, but you can squint and try. There’s velocity in that pen, yes, but every organization searches for velocity. “We have a lot of slider pitchers,” pointed out Ottavino. And it’s true: only the Astros pen has thrown more sliders this year. Sliders suffer the effects of altitude a little bit less than other pitches, so that’s no surprise.

But the slider isn’t really the best pitch either for McGee and Rusin, bedrocks of the pen. Instead, it might be about the fact that many of these pitchers have had to figure out how to pitch in Coors.

“BABIP in Coors field is by far the highest in baseball,” said McGee. “Huge outfield, so many hits drop in.” They moved the fences out at Coors to mitigate the home runs, and now it’s the easiest place in baseball to get a hit — overall BABIP in Denver is .321, fifteen points higher than the second-easiest place to get a hit this decade.

So you have to learn to recalibrate, to laugh off a couple bloop hits, and to move on. “If you’re going to give up a run, keep it at one run at a minimum,” said Ottavino. “Everyone’s learned how to use their stuff, and work hard together,” said Rusin of the extra hits in Coors.

When to work out, when to catch some Zs, how to throw your sinker at home and away, how to laugh off the extra hits — these are the tricks of the trade you learn over time, and why it’s important, when you’re building a bullpen in Denver, to make sure you’ve got some guys with experience up a mile high. It’s different up there, you might have heard.