Olson collected his 10th home run in Tuesday's 8-2 loss to the host Angels, joining Chapman (10) and Pinder (12) in double-digit territory and giving the A's three rookies with 10 homers or more for just the second time in Oakland history.
The only other instance came in 1977, when Wayne Gross, Mitchell Page and Tony Armas teamed up to accomplish the feat.
"We're excited about this group, and they're getting a chance not only to play and get some regular at-bats, but they're getting to do it together, too," A's manager Bob Melvin said.
"It's nice that we can all be up here and get this chance," Olson said.
The A's have relied heavily on the long ball this year, almost to a fault. Their home runs have accounted for 279 of their 579 runs (48 percent), while finding other ways to score has been an ongoing struggle. Most recently, the A's are 15-for-86 (.174) with runners in scoring position over the last 12 games -- and their only one in four chances Tuesday was an infield single from Khris Davis that didn't plate a run.
As a result, the A's dropped their second straight to the Angels, following a three-game sweep of Texas at home.
"We came off a real good series, and we have not played too terribly well here these two games," Melvin said. "We have to give them a better fight, but these guys have an expectation as a group, and it's fun to watch them together, because they really support each other, and they're going to be part of our future. We're going to have some ups and downs, but we're excited about where we're going with these guys."
Olson is hitting .309 with six home runs and 11 RBIs in 18 games since being recalled from Triple-A Nashville on Aug. 8, taking advantage of his first extended opportunity at the Major League level.
"He can hit," Melvin said. "He draws his share of walks, he's finally getting comfortable and getting to play a good portion of the time, and he's going to hit homers, he's going to get on base, and he plays a terrific first base. This is the first real opportunity he's gotten, and he's taking advantage of it."
"Oly's special," starter Chris Smith said. "Some of these young guys are pretty special in my household. Playing with them the last two years now, my daughters, that's their favorite guys out there. You've got Chapman, Olson, Pinder … These guys are the fan favorites in my house. They just think it's special that their dad gets to play with those guys. When I see them on the field, I tell them all the time, they're special players."
Jane Lee has covered the A's for MLB.com since 2010.