It was a milestone night for both. LaRoche tied a career high with four hits -- all singles, as noted by Diaz. He missed out on a career-best five hits in the ninth when he walked on a 3-2 pitch.
Of course, with LaRoche on base again, Diaz, batting behind him, grounded into his third double play of the night. That was his career high (he had never had more than one before) and tied a franchise record.
Strangely, in Wednesday's 6-2 Atlanta win over San Diego, Diaz gained some company, as the Padres' Kevin Kouzmanoff tied a franchise record by hitting into three double plays -- in the first, fourth and sixth innings.
"[Braves starter] Tommy [Hanson] made some good pitches on Kouz," said Diaz. "And he hit the ball really hard at Chipper [Jones, who turned a 5-4-3 double play in the fourth]. Sometimes, the harder you hit it, the easier it is to turn a double play. Unfortunately for Kouz, he hit it right at Chipper.
"I don't know the last time that ever happened on back-to-back days in the same stadium, but it was pretty ironic."
However, Diaz and Kouzmanoff both fell one short of the Major League record of four, which was set by Goose Goslin of the Tigers (April 28, 1934) and Joe Torre when he played for the Mets (July 21, 1975).
Diaz tied a Braves franchise record, held by Walt Cruise (vs. Cincinnati, Sept. 13, 1921) and Joe Adcock (vs. Pittsburgh, July 20, 1955).
However, Diaz did something that no Brave has done since the club moved to Atlanta in 1966, and that is hit a home run along with a hat trick of double plays in the same game.
It was Diaz's two-run homer, his fifth of the season, to the short porch in right field that capped a four-run sixth inning. Scott Rolen was the last Major Leaguer to hit into three double plays and hit a home run, and he did it for St. Louis against Cincinnati on Aug. 27, 2002.
"It was a pitch I was able to put the barrel on, and insided it out and it found the short part of the yard," Diaz said.
As for the double plays, Diaz said, "To hit into double plays is a testament to the guy batting in front of you, because he was on base all night long. And I had plenty of opportunities.
"Actually, the first two double plays, I was totally fine with. The first one, I hit a line drive up the middle off the pitcher's glove, and it deflected to the second baseman. The second one, I was just trying to put any ball in play. I had two strikes, with the pitcher batting behind me and nobody out. I don't want to put him in a situation where he can end the inning with a double-play ball. We needed to get at least one run, and we did."
Diaz was on the bench Wednesday as Ryan Church returned to right field after missing six games with a sore right elbow.
Church responded by collecting a pair of singles, and he drew a walk and threw out Chase Headley, who tried to tag up from third in the fifth inning.
"I felt good, no pain and it was good to be back out there," said Church.
While Diaz found the short porch on Tuesday, LaRoche found a lot of holes all over the field as he continued his amazing assault on PETCO Park.
LaRoche came into Wednesday's game hitting .351 with seven home runs and 18 RBIs in 21 games at PETCO.
He extended his hitting streak to five games on Wednesday with a single in the second inning and scored the team's second run on a single by Nate McLouth.
"I think it's all pretty much a coincidence, nothing more," said LaRoche. "I am comfortable here. It has a good backdrop as far as seeing pitches. I don't have to fight shadows or glares or anything.
"I've gotten pitches to hit here and made the most of it, nothing more than that. And I've been lucky. The ball travels well here. I've heard it can be a graveyard and the ball just dies here. I'm sure it is that way for a lot of the year, but when I've come in my six years, it's been late in the summer and the ball just seems to fly out there."