On Dec. 29, 2022, the Dodgers signed J.D. Martinez to a one-year, $10 million deal. The move came and went without much fanfare, paling in comparison to some of the astronomical contracts that were signed earlier in the month.

Martinez, a 35-year-old designated hitter coming off a season in which he hit .274 with 16 homers and a .790 OPS for the Red Sox, ended up being the biggest addition the Dodgers made last offseason. Meanwhile, they had several notable departures, including Trea Turner, Cody Bellinger, Justin Turner, Tyler Anderson and Andrew Heaney.

As a result, it was easy to predict that this would be the year the Padres overtook the Dodgers in the NL West. After all, San Diego knocked off Los Angeles in the NLDS last year and signed Xander Bogaerts to an 11-year, $280 million contract in December, adding another All-Star to a talented roster that was only going to get stronger once Fernando Tatis Jr. returned from suspension in April.

However, more than two months since Opening Day, L.A. is right where it always is, among the best teams in baseball. The Dodgers have a 35-26 record, one game behind the surprising D-backs for first place in the NL West. They’ve done that without their usual pitching mastery, posting the fourth-highest ERA (4.52) in the NL.

While its pitching has been lackluster, Los Angeles’ offense has flat-out bludgeoned opponents, ranking third in MLB in runs per game (5.56) while averaging a half-run more than any other NL team.

Of course, the quartet of Freddie Freeman, Mookie Betts, Will Smith and Max Muncy is owed a good deal of credit for the Dodgers’ offensive success this season, but we also need to spotlight Martinez, who has turned back the clock and rediscovered the pop that once made him one of baseball’s most feared sluggers.

Martinez already has 15 homers -- one fewer than he hit all of last season -- and is leading the NL with a .633 slugging percentage through 45 games with the Dodgers. Given all the time Bryce Harper missed while recovering from Tommy John surgery, Martinez has a strong case to be the NL's starting DH at the 2023 All-Star Game in Seattle.

It’s a far cry from 2022, when Martinez’s power disappeared for long stretches. The veteran hit one homer over 15 games in April 2022 and went deep just six times in 96 games from May 18-Sept. 18, with homerless droughts of 34 games, 22 games and 19 games -- his three longest home run droughts since the start of 2014 -- during that time frame.

There’s been nothing fluky about Martinez’s renaissance. In fact, only two hitters across MLB entered play on Tuesday with a higher expected slugging percentage, which is based on quality of contact (rather than actual results), plus strikeouts: Aaron Judge and Ronald Acuña Jr.

Highest xSLG, 2023:

1. Aaron Judge (NYY): .761
2. Ronald Acuña Jr. (ATL): .654
3. J.D. Martinez (LAD): .643
4. Freddie Freeman (LAD): .611
5. Luke Raley (TB): .600

Martinez’s xSLG is up 172 points from 2022, marking MLB’s largest year-over-year increase.

We can pinpoint two major reasons why his power has returned in 2023. (All stats below are through Monday.)

1) He’s producing more hard-hit fly balls

As usual, Martinez was one of the leaders in producing sweet-spot contact (batted balls with a launch angle ranging from 8-32 degrees) last season, so he was still hitting the ball in the air frequently.

What he didn't do as much, however, was hit the ball hard (95+ mph exit velocity), especially on fly balls.

That's changed in 2023, with his hard-hit rate increasing a whopping 13.1 points -- the largest spike in MLB. This includes a 16.5-point increase (47.9% to 64.4%) in his hard-hit rate on fly balls.

With a 54.8% hard-hit rate overall, Martinez is back among the elite in that department (96th percentile) after falling to the 60th percentile in 2022.

Hard-hit fly balls comprise more than 23% of his batted balls in 2023, up from 14.8% a year ago.

Relatedly, Martinez has recorded 23 batted balls that were classified as barrels, balls with the optimal combination of exit velocity and launch angle, typically resulting in extra-base hits. His 18.5% barrel rate (up 6.0 points from 2022) ranks in the 97th percentile.

2) He’s pulling the ball more

Arguably no hitter in the Statcast era (since 2015) has been as effective as Martinez at hitting for power to the opposite field.

But in 2022, Martinez’s slugging percentage on opposite-field batted balls plummeted to .509, down from .825 (fourth highest in MLB) across 2015-21. It’s in the .500 range again in 2023, but he has counteracted the decline by producing more pull-side contact, to great effect.

Martinez’s pull rate is up 6.3 points from 2022, and only a select few players have a higher slugging percentage when they pull the ball than Martinez’s 1.106 mark.

Just seven of his 48 hits and four of his 30 extra-base hits have gone to the opposite field in 2023.

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It should be noted that Martinez also started off strong in 2021 and 2022, only to peter out as the year progressed. At 35 years old, it's certainly possible that will happen again this season. But right now, he's on track to go down as another big win for the Dodgers' front office.