NEW YORK -- If not for Chris Stewart straining his left hamstring while legging out a triple on Monday, Elias Diaz would have been with Triple-A Indianapolis on Friday night. If not for the illness that sidelined Francisco Cervelli, Diaz would have spent the series opener at Citi Field in the Pirates' dugout.
But Cervelli was scratched 25 minutes before Matt Harvey's first pitch, and Diaz took full advantage of the unexpected opportunity. The 26-year-old catcher powered the Pirates' 12-7 win over the Mets, going 2-for-5 with a double and his first Major League homer.
First called up in September 2015, Diaz entered Friday with only two big league hits, one RBI in nine games and no idea he'd be starting against the Mets. He ended the night with Pittsburgh's first six-RBI game since Neil Walker on Sept. 23, 2015, the first six-RBI game by a Pirates rookie since Andrew McCutchen on Aug. 1, 2009, and the first six-RBI game by a Bucs catcher since Don Slaught plated seven on July 2, 1993.
"This has been an incredible evening, something that embarks my journey in this career and something that I'm looking forward to," Diaz said through interpreter Mike Gonzalez.
Cervelli reported to Citi Field unable to play, manager Clint Hurdle said, so Diaz was called into action. The Pirates' No. 9 prospect huddled with starter Gerrit Cole, formulating a game plan, then went to work.
"What a game. I'm sure it's one he'll remember for a long time," Cole said. "Just a really tremendous game from him. He should be really excited."
The Pirates all but wasted a bases-loaded, nobody-out situation in the first inning, scoring one run on a fielder's-choice grounder by David Freese. Diaz wouldn't let a similar opportunity slip by in the fourth.
With one out and the bases full, Diaz clobbered Harvey's 87.8-mph slider into the left-center-field gap for a go-ahead three-run double.

With the Pirates down by two and Harvey out of the game in the sixth, Diaz lashed an 88-mph fastball from reliever Paul Sewald for his first homer, a three-run shot that traveled a projected 419 feet to left-center, according to Statcast™.
"It had nothing to do with whether Diaz was a late [addition], whether Cervelli was supposed to be in there," Sewald said. "I had the information. I just didn't make a great pitch."
In Pittsburgh's dugout, Josh Bell screamed for Diaz's line drive to get up and reach the seats.
"Then I looked," Bell said. "I was like, 'That ball doesn't need to get up at all. It's already out.' He hit that ball on the nose. It was really impressive. We were all freaking out for him."

Diaz eventually received the ball and placed it on a shelf in his locker. During a postgame interview, he picked it up and smiled.
If not for a series of injuries, this moment may have come last year. Diaz was one of six catchers the Pirates employed in 2016, but the timing of his various maladies -- an elbow injury that required surgery in May, an infected left leg that ended his season in September -- limited him to just one game in Pittsburgh. That misfortune followed him into the offseason, when he was shut down with an oblique injury while playing winter ball.
When the Pirates needed a third catcher, Diaz was hurt. When he was healthy, so were Cervelli and Stewart. But when the Pirates needed Diaz on Friday night, he was ready.
"I'm very grateful. Yes, I have gone through a lot, but these are the things that have helped me get here," Diaz said. "I've kept my head up. I've kept working hard. I'm just glad to be here. This is my career."