An Early Look at Batted Ball Velocity in the 2015 MLB Season

Newly released data can tell us how fast a batted ball left the hitter's bat, and this could be a huge tool for player analysis.

This season, MLB Advanced Media has made a hitter’s exit velocity publicly available, information that could prove to be very valuable and help us get closer to stripping away luck and random variation when assessing players.

The benefit of looking at how fast the ball leaves the bat is that we can look at how hard the ball was hit, independent of the at bat’s outcome. We currently have batted balls broken down into line drives, ground balls and fly balls, but this should improve our analysis, given not all line drives, ground balls and fly balls are the same, and sometimes the distinction between a fly ball and liner can be arbitrary.

Mike Axisa of the essential Yankees blog River Avenue Blue rightly notes that we don’t have enough of this data to know when it stabilizes, or how it correlates to itself or actual offensive success.

Still, by stripping away ball-in-play luck, it’s possible exit velocity and other defense-independent hitting stats could do for offense what Voros McCracken did for pitching.

We’re not there yet, but we can certainly use the exit velocity data currently available in conjunction with other, more established stats.

For example, Hanley Ramirez’s his .268 ISO suggests the new Red Sox outfielder has been crushing the ball. His league-leading 100.97 batted ball velocity surely backs this up (via Baseball Savant).

Here are three other inferences we can make about the young season with this new data.

Jason Kipnis Has Been Unluckier than We Thought

In 2013, Kipnis posted a 129 wRC+, which was third in the big leagues among second baseman. The Indians second baseman slashed .284/.366/.452, with an 11.6% walk rate, and while his .345 BABIP seemed bound to regress, a 24.7% line drive gave that figure some legitimacy.

Last season, the liner rate remained above average (22.6%), but the BABIP dropped to .288, taking Kipnis’ average down to .240, despite an improvement in terms of strikeout rate. He did not seem to be particularly unlucky on line drives, given he hit .708 on his liners, according to FanGraphs.

The BABIP monster did get him on grounders and fly balls, though, as the average ground ball and fly ball produced batting averages of .239 and .207 in 2014, respectively, Kipnis hit .179 on his grounders and .163 on his flies.

We do know he did not hit many infield flies (posting a 3.2% IFFB rate, which was well below the league average of 9.6%), but aside from that we do not know much more about what kind of ground balls or fly balls Kipnis was hitting. Exit velocity would have been very helpful.

In 2015, Kipnis is still posting a solid 22.0% line-drive rate, but his BABIP has dropped further, to .260. His infield fly rate has spiked to 12.5%, so this does a good job of explaining his .071 average on fly balls, while he is hitting .261 on grounders.

On line drives, though, he is 6-for-11, good for a .545 average which is well below what we should expect (the big league average on liners was .685 last year).

Given the high infield fly rate and his BABIP last year, perhaps Kipnis just isn’t hitting the ball hard.

Exit velocity tells a different story.

Kipnis’ average ball in play has left the bat at 90.89 miles per hour, according to Baseball Savant, ranking 17th among the 49 players in MLB with at least 30 at-bats (Axisa found the league average to be 88.2).

His average line drive has left the bat at 99.14 mph, ranking 14th among the 177 players with at least five line drives this season.

Among the 142 players to face at least 200 pitches these year, Kipnisis 13th in percentage of pitches he’s seen resulting in a batted ball over 90 mph (9.01%). Kipnis is 8-for-21 on these plays, with seven singles and four fly outs on balls hit over 340 feet.

Major League hitters have combined to hit .436 on balls in play hit over 90 mph this season, while Kipnis is hitting .381 on them to rank 21st among 26 players with at least 20 at bats in which they reached this exit velocity.

This data, coupled with a batting average on line drives roughly .200 points lower than what we would expect it to be, we can strongly imply Kipnis has been unlucky to start the season.

A-Rod Really Is Back

Love him or hate him, Alex Rodriguez has produced like one of the best players in baseball history, ranking 14th all-time in fWAR among position players and fifth after World War II.

Expectations for his return in 2015 from last year’s suspension, though, were low, considering he is 39 and came into the season with just 44 games played since 2012.

It’s early, yes, but these expectations look to be off.

Rodriguez has mashed to the tune of a .265/.419/.571 slash line with a four home runs and a 172 wRC+ in 62 plate appearances.

And, oh yea, he has hit the crap of the ball.

He is second to Ramirez in terms of average batted ball velocity, with the ball leaving his bat with an average speed of 97.62 miles per hour.

On balls that have left his bat faster than 90 mph, Rodriguez is hitting .500 with a 1.250 slugging percentage and three home runs. None of these hits was louder than a 471-foot home run he hit against the Blue Jays on April 17th that had a velocity of 107.0 mph.

A more patient approach at the plate (21.0% walk rate, 41.4% swing rate) has been another huge factor in A-Rod’s resurgence, but it’s been nowhere near as fun watching him launch 450+ moonshots (unless you hate the guy; then none of it has been that fun).

There’s Reason for Optimism for Two Embattled Boston Pitchers

This data has a ton of applications for hitters, but can also be of use when evaluating pitchers.

We have to be even more cautious with pitchers, though, as while it can definitely show that a pitcher is getting hit hard, we don’t know yet if exit velocity allowed is relatively consistent or prone to variation like BABIP.

That being said, this new information may provide some comfort for Boston fans distressed over Justin Masterson and Clay Buchholz's lackluster results.

Buchholz and Masterson are fifth and sixth, respectively, in terms of their ERA minus FIP this season, as while both spot solid peripherals, it hasn’t yet translated into run prevention.

Knowing what we know about defense independent pitching, we can pretty confidently predict that Buchholz (144 ERA-, 78 FIP-) and Masterson (139 ERA-, 72 FIP-), will both soon see their ERAs drop.

And while neither have a history of significantly underperforming their peripherals (Masterson has a career ERA- of 106 and a FIP- of 95, while Buchholz is a 93 and 100), it would not be unreasonable to assume both could struggle to manage contact, given the big disparity in run prevention and defense-independent stats.

A look at exit velocity in conjunction with their batted ball profiles should ease these concerns.

Masterson ranks 36th in terms of lowest exit velocity allowed (87.22 mph), so his worse-than-average BABIP certainly seems like a product of bad luck, rather than getting hit hard.

Buchholz’s average batted ball allowed travels 88.56 mph, which is slightly higher than league average, but comes nowhere close to explaining an ungodly .404 BABIP.

It’s been pretty well established that pitchers have minimal control over what happens to the ball once it leaves the bat, though there are some instances when a pitcher gets hit so hard, we’re forced to look beyond his peripherals (looking at you, Joe Blanton).

Based on the exit velocity data, imperfect and new as it may be, we can probably assume luck and random variation have driven Buchholz and Masterson’s poor BABIPs more than allowing hard contact, so regression should be in order.