The Marlins’ Luis Arraez And The Quest For A .400 Batting Average

Baseball is, and has always has been in part a game of numbers. Often a game of round numbers. Of .300 and .400 batting averages, of 30, 40, 50, 60 and even 70 homers, of 100 RBI, for hitters. Of 20 and even 30 wins, 3.00 and 2.00 ERAs for pitchers. The game has evolved (and at times devolved) over the years, and statistical analysis has brought new and arguably more important numbers like on-base and slugging percentage and weighted runs created (wRC+) and weighted on-base average (wOBA) for hitters and fielding independent pitching (FIP) for pitchers. But the old standards die hard.

And as the game has morphed into its modern form, some previous player archetypes have disappeared. Pitchers don’t pitch 300 innings anymore, and 20 wins in a season have become a stretch even for the game’s greatest starters. 30 wins is a pipe dream. Offensively, the game has become more power-focused, with launch angle all the rage, and batting average de-emphasized, much like the importance of the running back in the modern NFL.

But over there in the corner waving hello is Marlins’ second baseman Luis Arraez. He is a throwback’s throwback. His considerable value is almost totally balled up in his batting average. He gets there by bucking the trend in various ways. While many hitters pop up quite often in pursuit of a higher launch angle, Arraez never does. As increased fly ball rates have left behind the humble line drive, Arraez annually ranks among line drive rate leaders. Most importantly, while strikeouts rates have spiked throughout the game, Arraez almost always puts the bat on the baseball. Despite a relatively modest walk rate, he is one of a small but growing vanguard of MLB players who dares to walk more than he strikes out.

Arraez is a career .320 hitter who won his first batting title in the AL last season with the Twins with a .316 average. He was dealt to the Marlins in the offseason in exchange for newly-extended starting pitcher Pablo Lopez in a trade that has made both clubs ecstatic in the early stages of the 2023 season. You see, through Monday’s games, Arraez had taken things to another level altogether batting average-wise, hitting .458 with a .508 OBP and .610 SLG.

Obviously, small sample size caveats apply here. But is there anything new going on, and is a .400 batting average actually possible in today’s offensive environment?

WHY HE COULD DO IT

• Low Strikeout Rate – Arraez has never posted a strikeout rate over 10.0% in a season. In 2022, his K rate dropped to a career-best 7.1%. So far in 2023, it’s even marginally lower than that at 6.2%. We likely can’t expect it to drift much lower, but that’s OK.
• Non-existent Pop Up Rate – Arraez has never posted a pop up rate rate over 1.3%. Last year, it was just below that at 1.2%. Thus far in 2023, he hasn’t popped up. He never popped up in the pandemic-shortened 2020 season, either.
• Very High Liner Rates – MLB hitters bat over .650 on line drives, so it stands to reason that hitters with a knack for hitting them tend to compile high batting averages. Thing is, liner rates are quite volatile from season to season for most hitters, though a small group consistently scores high in this area. Arraez is a charter member of this group. His 2022 25.3% liner rate was simultaneously over two standard deviations higher than league average – and a career low. (He’s beneath that level at 24.1% thus far in 2023.)
• Some Sort Of “It” Factor That Is Hard To Define – In all but his 2019 rookie season, Arraez has outperformed his “Tru” Production+ level – my batted ball-based proxy for wRC+. He appears to have some sort of innate ability to “hit ‘em where they ain’t”. He doesn’t just do this on an overall basis – he seems to overperform his Adjusted Contact Score on each batted ball type, each year.

WHY HE ABSOLUTELY WON’T DO IT

• He Just Doesn’t Hit The Ball Hard Enough – Sure, having an elite batted ball frequency profile will get you far, but to be an elite hitter it sure does help to have a strong batted ball authority ball profile, and Arraez clearly falls short on that front. His overall average exit speed has never exceeded the average range. And when you break it down by batted ball type and season, only his 2022 average grounder exit speed was materially above league average. While his 2023 average fly ball exit speed is a career high, it still sits in the “can of corn” range, while his average liner exit speed is just above his career low, and his average grounder exit speed is sharply down from 2022. Most strikingly, Arraez has hit exactly one batted ball at 100 mph or higher this season.
• He Hits Too Many Fly Balls – While Arraez never pops up, his fly ball rate has been creeping upward in recent seasons, and at 35.1% thus far in 2023, is dangerously close to being materially above average. For most hitters, that’s a good thing. When you almost never hit the ball at 100 mph or higher, it can be fatal. 85-95 mph fly balls are basically outs. Based on the exit speed of his fly balls, his Adjusted Fly Ball Contact Score was 39 in 2022, and even lower at 34 in 2023. Of course, he has that “it” factor we discussed above going for him, so his actual or Unadjusted Contact Score have been much higher at 63 and 97.

Based on his overall batted ball profile, Arraez “should have” batted .275-.336-.393 in 2022. Obviously, he blew past that and won the batting title. So far in 2023, he’s projected to be almost the same exact player, with a .274-.341-.395 line. When Luis Arraez comes to bat, you’re very likely to see an 85-100 mph fly ball, an 85-100 mph liner or an 85-100 mph grounder.

What is his absolute ceiling? Let’s say he never pops up in a season (he’s already done that once). Let’s say he posts a 5% strikeout rate over a full season (unlikely but within the realm of possibility). Let’s say he posts a 30% liner rate (he’s already reached 29.4% twice). That would net have netted him 24 more line drives in 2022, and at his liner batting average, 17 more hits. That would have raised his batting average from .316 to .347 – still not very close.

Right now, he’s batting .458 because of unsustainable liner and grounder Unadjusted Contact Scores of 164 and 406, respectively; he’s hitting .909 on liners and .429 on grounders. His current overall Unadjusted Contact Score of 192 was exceeded by exactly one major leaguer in 2022 – Aaron Judge, who destroys the baseball. It would be a major achievement for Arraez to ever post a seasonal Unadjusted Contact Score over 100, or league average. His 97 mark in 2022 is his career best. Yes, even with all the liners he does and pop ups he does not hit, his lack of overall batted ball authority and high frequency of can of corn fly balls is a major limiting factor.

Batting average has been stripped of its former lofty status, but it still has value. Arraez and his merry band of Steven Kwans and Jeff McNeils have brought it back into style, at least somewhat. To hit .400, however, lots of things have to happen. Beyond what Arraez already does, he’d have to turn a ton of outs into walks (unlikely) and hit the ball a LOT harder to turn some of his fly balls into extra base hits (not going to happen). He’s not a speedster, so leg hits aren’t really an option. The current version of Luis Arraez has a batting average ceiling of roughly .350. Let’s enjoy his hot start and see where his pursuit takes him.