Zac Gallen vs. Merrill Kelly.

Two years ago, it was a barstool debate spawned by one of the most popular teams in franchise history. Who was the real ace of the 2023 Diamondbacks?

After watching Kelly dominate the postseason, winning road game after road game, I declared that the challenger had stolen the crown, that Gallen was the team’s ace in name only.

Gallen responded by nearly throwing a no-hitter in Game 5 of the World Series.

On Wednesday, Gallen will actually face Kelly in a Texas-sized showdown. Gallen is pitching to save Arizona’s season, even though playoff hopes are but a flickering flame. Kelly is hoping to do the same for the Rangers, a team whose torch burns brighter. Both are free agents after the season, obviously incentivized to finish strong.

This will be great theater. Gallen has been highly erratic this season, but he has won his past two starts. Beating Kelly in Texas would add heft to his late-season resume. After all, Kelly is the hired gun acquired at the trade deadline, tasked with pushing the Rangers over the top. Gallen went untraded and unwanted.

For Kelly, it’s a chance to further his reputation as a big-game assassin, the kind of cold-blooded athlete who can elevate and execute above all the hype and noise. Kelly was 30 years old when he made his Major League debut in Arizona. He’ll turn 37 in October. If Kelly can sizzle and dazzle through another postseason, he may yet find that big contract.

I would also love to watch Gallen finish like a real ace, like the guy who once strung together 44.1 scoreless innings, the seventh-longest streak in MLB history. Too frequently, recency bias is ruining sports, making fans lose their minds and their context.

There was a time when Gallen and Kelly were the modern equivalent of the Randy Johnson and Curt Schilling tandem. Their lockers were next to each other. They golfed together. They fed off each other’s success. They once won successive National League Pitcher of the Month honors, something that hadn’t been done since Johnson and Schilling.

Diamondbacks’ ace reporter Todd Walsh remembers walking into the clubhouse in Detroit right before the trade deadline. Tension was thick in every corner, and the room was largely silent. But Kelly and Gallen were sitting comfortably at a small table, face-to-face, because they were truly good friends and very comfortable in each other’s company.

But how will they look on Wednesday? It’s practically appointment television. Because we all know how much Gallen and Kelly care about each other, the Diamondbacks’ franchise and baseball fans in Arizona.

Reach Bickley at dbickley@arizonasports.com. Listen to Bickley & Marotta weekdays from 6 a.m. – 10 a.m. on 98.7 FM Arizona’s Sports Station.