J.D. Martinez hit 29 home runs for the Diamondbacks. He was acquired in July

A big reason why the Arizona Diamondbacks found their way back into the postseason one year after losing 93 games is the midseason addition of outfielder J.D. Martinez, who has been a power-hitting machine since joining Arizona.

Arizona will host the Colorado Rockies on Wednesday night in the National Legue WIld Card Game (8 p.m. ET, ESPN, WatchESPN).

Martinez hit 45 home runs in 119 games in 2017, just the fourth player in MLB history to hit 40 or more homers in a season playing 120 or fewer games.

Twenty-nine of those home runs have been hit since joining the Diamondbacks, for whom he is hitting .302/.366/.741. His first game with Arizona was on July 19. That’s a ridiculous 29 home runs in just 62 games with his new team, just one fewer than Giancarlo Stanton of the Miami Marlins during that time.

“He’s had a phenomenal run with us, and we’re happy he’s here. He’s definitely added a different element both for right-handed and left-handed pitching,” Diamondbacks general manager Mike Hazen said Tuesday. “At that point in the season we were struggling a little bit vs. lefties. That has rectified itself in the second half to some degree. And we also continue to play well vs. righties. So he’s been a big difference maker for us in the second half.”

Martinez hit the third-most home runs in major league history after getting traded midseason. The last with more was outfielder Gus Zernial, who hit 33 home runs for the Philadelphia Athletics after a trade in 1951.

Zernial played just four games for the Chicago White Sox to start that season before getting shipped to Philadelphia as part of a three-team trade. That deal happened on April 30.

Martinez was traded to the Diamondbacks on July 18.

The other player to hit 30 home runs after a midseason trade was Hall of Fame outfielder Goose Goslin, who had seven home runs in 47 games for the Washington Senators in 1930 before getting shipped to the St. Louis Browns on June 13. Goslin hit 30 home runs for St. Louis in 101 games.

Again, Martinez has 29 home runs in just 62 games for Arizona.

Martinez combines with perennial MVP candidate Paul Goldschmidt — who hit .297/.404/.563 with 36 home runs in 2017 — to give the Diamondbacks a dangerous duo in the middle of their lineup.

“There is no doubt he’s been a huge impact on their lineup. When you put those two guys back-to-back, I mean, it’s formidable. Those guys are, you know, two of the best hitters in the game,” Rockies manager Bud Black said. “J.D. has had a phenomenal second half here in Arizona. They’ve made a tough lineup tougher. I guess that’s as simple as I could put it.”

September was especially powerful for Martinez, whose 16 home runs tied a National League record for the month, matching Ralph Kiner. In 25 games in September, Martinez hit a whopping .396/.431/.950, earning NL player of the month honors.