The results: a homer from the right side of the plate in the fourth inning to open the scoring, and a mammoth shot from the left side in the ninth that proved to be the game-winner.
"It was just Nick and the coaches ... it was like he was challenging himself," Geren said. "He took his time, asked us to present him with certain situations, and just got down to business. It was very impressive.
"[It was] one of the best [batting-practice] sessions I've ever seen."
With his first homer, a two-run shot into the left-field bleachers with nobody out in the fourth off O's starter Erik Bedard, was the 61st career homer for Swisher, moving him past Ruben Sierra and into first place among Oakland switch-hitters.
"Did I pass him?" Swisher said after the game. "I was wondering why the ump gave me the ball the next time I was up. I was like, 'What are you doing?' But I ended up getting [the record], so that's pretty cool."
He then shook his head, smiled and said, "I'm in the record book for this now, and I'm in the record book for [being the victim of] Curt Schilling's 3,000th career strikeout, too. So I'm working my way up the ladder."
As is Putnam, who now sits a mere 4,255 knocks away from tying all-time hit king Pete Rose.
Putnam, 24, arrived in Baltimore earlier in the day -- he'd hopped on a 7 a.m. CT flight out of Texas -- after being called up from Double-A Midland to replace injured outfielder Milton Bradley on the A's roster, and he had an adventurous evening as Oakland's starting right fielder.
Before striking out in his first at-bat in the third inning, Putnam slammed into the wall in foul ground down the right-field line after making a fine backhanded catch of a fly ball off the bat of Jay Payton to end the second inning.
"Getting that first touch helped calm me down a little," Putnam said. "You want to get as many 'firsts' out of the way as possible."
"I'm in the record book for this now, and I'm in the record book for [being the victim of] Curt Schilling's 3,000th career strikeout, too. So I'm working my way up the ladder."
-- Nick Swisher, on setting a team record for homers by a switch-hitter
The first hit came when Putnam singled to open the top of the fifth inning, and he flagged down a deep drive into the gap in right-center with another tough running grab to rob Huff of extra bases to open the bottom half of the frame.
Putman's new teammates entertained themselves with the big-league tradition of defacing an imposter ball with various scribblings such as "The official scorer had a heart," but Putnam said he never even saw it. And unlike fellow rookie Travis Buck, who had to wait days to get his prized mementos, Putnam had the real first-hit ball and the lineup card in his locker by the time he got out of uniform after the game.
"I don't think it's sunk in what's going on here yet," he said. "But it's a lot of fun."
Last week, Haren talked about how much fun it was watching his fellow starters "feed off each other" while ripping off quality start after quality start. And his seven innings of five-hit, one-run work marked the 17th straight game in which an A's starting pitcher allowed three runs or less, establishing an Oakland record for such consecutive stingy starts in a single season.
But when asked if it was fun to be the guy to set the record, Haren blanched.
"Absolutely not," Haren said. "Every time out is completely different from the last time, and you don't ever want to be overconfident."
In truth, Haren's outing looked a lot like his previous work this season. He said he had command issues early on, but he walked one against five strikeouts over 98 pitches, and Brian Roberts' first homer of the year, a leadoff poke in the sixth that cleared the high wall down the right field line by about a foot, represented the only significant damage done against him.
A's starters have held the opposition to one run or less in six of the past seven games and 10 of 19 games this season.
"It's still early," Geren said, "but it's a great feeling as a team to know we're going to be in every game. Let's keep it going. I love it."
Added Haren: "I don't see a reason why we have to stop."
With the A's up 5-1, righty Kiko Calero took over for Haren to start the eighth and was relieved by Alan Embree with two on and two out. Huff pounded the first pitch he saw into the bleachers in right-center to cut Oakland's lead to one, but Swisher's moon shot to right off Danys Baez in the ninth gave Street some breathing room for the bottom half.
"I know it's Miguel Tejada, and he's a great, great hitter, but I like my chances with a clean count against a righty than down 2-0 against a lefty. I'm just glad it all worked out."
-- Huston Street
It was the seventh multihomer game of Swisher's career, and the third time he's homered from both sides in a game.
"If you ask a switch-hitter, it's rare you feel good from both sides," said Swisher, who later added that he and Van Burkleo have been working on getting his swings out of uppercut mode and into more of a downward attack on the ball. "I've been looking for something to click all year, and today I think I found it.
"After the early BP, we even went into the [indoor] cage and worked some more before regular BP. Ty's the best, man. I have to give him a lot of credit."
Street, who inherited a one-run lead with the bases loaded Sunday in Texas and promptly gave up a two-run single, walked Payton and gave up a double to Corey Patterson to open the bottom of the ninth, and Roberts singled up the middle with one out to again make it a one-run game.
But after Mora, trying to bunt for a single, was thrown out at first by Street as the potential winning run moved into scoring position, Street intentionally loaded the bases by walking lefty-swinging Nick Markakis, to whom he'd fallen behind 2-0, to face Miguel Tejada, who ended the suspense by grounding out to second base on the first pitch he saw.
"I know it's Miguel Tejada, and he's a great, great hitter," Street said, "but I like my chances with a clean count against a righty than down 2-0 against a lefty. I'm just glad it all worked out."