Only 17 players in MLB history have a higher career average than Gwynn. Beltre has hit below .280 in 10 of 12 seasons.
Yet, Beltre is putting together a season with few recent comparisons aside from Gwynn.
On pace, through June 15, for 22 home runs and 109 RBIs with a .333 batting average, Beltre is having an All-Star-caliber season. But it's his historic performance in two-strike counts that warrants the comparison to one of the greatest hitters of all time.
Logically, batting averages in two-strike counts are significantly lower than all other counts. Not only do strikeouts weigh down the numbers, but it's far less likely to get a good pitch to hit. The league average is a mere .184 in two-strike counts.
Beltre is hitting .339 with two strikes, best in the majors.
Over the past 20 years, there have been only four better batting averages with two strikes. Flirting with .400 all season, Gwynn hit .397 in two-strike counts in 1994. Three years later, he hit .358. Placido Polanco (.350 in 2007) and Orlando Palmeiro (.340 in 2000) round out the list that has exceeded Beltre's current two-strike pace.
Among Red Sox, only Nomar Garciaparra (.331 in 2000) has hit over .300 in two-strike counts over the past 20 years. You'd have to go back to Wade Boggs (.306 in 1989) to find another.
If you want a reason why a career .273 hitter is chugging along at .333, look no further than these two-strike counts.
Beltre entered this season as a .215 hitter with two strikes. Thus, his .339 average has accounted for 15 more hits in two-strike counts than his career history would suggest. Look at it this way: Take 15 hits away from Beltre, and .333 becomes .272 -- essentially his career average.
So how is Beltre doing it?
He's not striking out significantly less, nor has his notoriously weak plate discipline improved. Although Beltre often has quick at-bats, this isn't the case of a small sample size. He's on pace for 98 two-strike hits. The last player with more than 90 was Chuck Knoblauch in 1996.
Rather, it's largely the reflection of an uncanny ability to be productive with two strikes even when the pitch is out of the strike zone.
According to Inside Edge, the league batting average with two strikes on pitches out of the zone is just .091. Beltre is hitting .321 in these situations. Think about that. Beltre's batting average when chasing pitches with two strikes would be the third best overall batting average in the National League.
Overall, Beltre has 17 hits with two strikes and the ball outside the strike zone. Ichiro (16 hits) is the only other player in double digits.
"He's a guy that will battle every at-bat," Victor Martinez told the Providence Journal earlier this month. "He's more tough when he gets two strikes. He just goes out there and doesn't give any at-bats away. He really battles every at-bat."
Beltre isn't just the best hitter in the majors with two strikes. His .397 batting average with two outs also leads the majors, and is the best in the American League since Ichiro (.407) in 2001.
Extending innings and dominating pitcher's counts, Beltre has emerged as the ultimate lineup pest. In fact, with two strikes and two outs, he's hitting .406 (MLB average: .172), according to Inside Edge. Throw some runners in scoring position, and it jumps to .455 (MLB average: .166).
Can Beltre possibly keep up this historic pace?
One statistic that might answer this question is batting average on balls in play (BABIP). With two strikes, Beltre is hitting .494 when putting the ball in play, almost impossibly better than the league average of .290. In other words, about half the time Beltre puts the ball in play, it results in a hit.
Contrary to some arguments, BABIP is not purely a measure of luck. But at the same time, a .494 BABIP would be unprecedented, and is most certainly not sustainable. Consider that no player has put up a BABIP higher than .410 -- regardless of count -- in the past 20 years. Ultimately, more batted balls figure to find their way into gloves rather than holes.
It's easy to praise Beltre's aggressive style when he is hitting well, and that's just what manager Terry Francona did last month.
"When you watch him hit [with two strikes], it's not like he really cuts his swing down a ton. When you talk to him, he talks about trying to see the ball longer, which certainly makes sense to me," Francona said in May.
It may make sense when it works, but during an inevitable slump, nothing makes a hitter look worse.
Last season, Beltre hit just .184 with two strikes, which prompted the Seattle Mariners' coaching staff to encourage him to shorten his swing.
For now, everything is working for Beltre, as he rides his two-strike prowess into a potential All-Star appearance (which would be his first).
Beltre swings at a higher percentage of pitches (50.3) than any other Red Sox hitter. That has frustrated some disciples of the plate-discipline world. But as long as he remains productive, those voices will be muted.
Any critics are clearly discounting this simple possibility: Maybe all those swings are just Beltre's way of getting to two strikes as soon as possible.
Jeremy Lundblad is a researcher with ESPN Stats & Information. He provides statistical analysis for ESPNBoston.com.