Here's a fun fact: They both played exactly 161 games and hit exactly 14 home runs in Red Sox uniforms.
And now for a pretty good sign that Martinez's five-year, $110 million contract is going to end up more on the Manny Ramirez side of Boston's history with high-priced hitters: He already has 15 homers through his first 48 games with the club.
Martinez, 30, is also rocking a .328/.383/.645 slash line and, as of Thursday, a 174 OPS+. The latter ranked fourth in the American League behind only Manny Machado, Mike Trout and supernova-hot teammate Mookie Betts.
There may be no bigger fan of Martinez than Hall of Famer Frank Thomas, who declared the former Houston Astro, Detroit Tiger and Arizona Diamondback to be the best hitter in Major League Baseball in a recent Fox Sports segment.
"It was really cool," Martinez told Rob Bradford of WEEI.com. "My whole career, even in the offseason, everyone is kind of like, 'Who is this guy asking for all this money? Nobody knows who this guy is.' I've always been living in the shadows of Miggy [Cabrera] and all these guys in Detroit. It's cool to get some recognition for it."
For what it's worth, Thomas' take isn't actually that hot.
- 1. Mike Trout: 177 OPS+
- 2. Joey Votto: 159 OPS+
- 3. J.D. Martinez: 151 OPS+
- 3. Giancarlo Stanton: 151 OPS+
- 5. Freddie Freeman: 149 OPS+
The argument for Martinez gets even more compelling if you strip the term "hitter" down to its essence. He is neither the best at drawing walks nor at making contact. But when it comes to how he hits the ball, he certainly stands apart.
Martinez was once asked by FanGraphs' Travis Sawchik about his approach to hitting, and he not-so-coyly replied: "I'm not trying to hit a f--king line drive or a freaking ground ball. I'm trying to hit the ball in the air. I feel like the ball in the air is my strength and has a chance to go anywhere in the park."
This approach hasn't propelled him to become the best air-ball (i.e., fly balls and line drives) hitter in MLB, but it has made him the league's leading specialist in well-hit air balls. These are otherwise known as "barrels," or batted balls that have an ideal combination of launch angle and exit velocity.
One of the knocks against Martinez in free agency was his proneness to injury. And that wasn't altogether unfair, given that he'd been limited to 239 total games across the two prior seasons.
Still, perhaps more attention should have been paid to how he still racked up more barrels (182) between 2015 and 2017 than every hitter except Nelson Cruz (192), who played in 65 more games.
On paper, a habit like this should find success anywhere. But if there was a concern about Martinez in Boston, it had to do with how his penchant for barreling the ball didn't come with a tendency to pull it.
He prefers to launch balls up the middle and to the right of center field. These are notably not areas where Fenway Park has a short porch that beckons most right-handed sluggers.
Although Martinez has a 1.187 OPS and nine homers at Fenway this season, his new digs probably have cost him some production. If he called, say, Yankee Stadium home, several of the barrels he's hit at home would have yielded better results:
However, to ask Martinez to pull more balls would be to ask him to change a fundamental aspect of his approach.
When he was asked about his non-Fenway-friendly hitting style in an MLB Network interview, Martinez dropped this little nugget: "I drive the ball up the middle to the big part of the field. I think it helps me stay on more pitches, it keeps me longer in the zone."
The proof of this can be seen when Martinez is actually hitting. He stays balanced as well (or better) as any hitter in the game. He swings and misses a lot, but it seems like he rarely swings too late at a fastball or too early at an off-speed pitch.
And as time goes on, Martinez is only becoming a greater master of the strike zone. Per the most detailed zone map available at Baseball Savant, his rates of in-zone swings and in-zone barrels are on the rise:
Even if Fenway has robbed Martinez of some base knocks, it's possible that they're more than being accounted for based on how Betts has benefited from having him around.
The arrival of Martinez in Boston's lineup has coincided with a dramatic increase in Betts' barrel rate and his MLB lead in that department. It evidently has something to do with how he and Martinez have become partners in hitting crime.
"It's kind of like having a kindred spirit," Martinez told Julian Benbow of the Boston Globe.
"I ask him and he tells me what he thinks, what to do," Betts responded. "He's had so much success, it'd be silly for me not to try and do it at least. And he hasn't steered me wrong yet, so I kind of trust in him."
As of now, Martinez and Betts are the first pair of teammates with an OPS+ north of 170 since Albert Puiols and Jim Edmonds of the 2004 St. Louis Cardinals. They are the beating heart of the Red Sox lineup, not to mention the driving force behind the team's MLB-best 34-16 record.
In the short run, all this could end up leading the Red Sox to their first World Series in five years. In the long run, it'll serve as a reminder not to be afraid to spend on free agents.
Every so often, it works.