Jack Hannahan was out of the starting lineup. Nomar Garciaparra was in. Jack Cust was dropped to the No. 7 hole.
It wasn't enough, though.
A late-inning rally led to seven runs against the Colorado bullpen, but it was too little, too late as the Rockies held on for an 11-9 win Saturday night.
"The way we came back at the end shows some heart," Geren said. "They don't quit. ... Being down 11-2, though -- it's hard to come back against that."
Adam Kennedy singled home Cust in the seventh to get the Oakland comeback rolling.
Cust and Bobby Crosby delivered back-to-back RBI singles in the eighth, scoring Daric Barton and Hannahan, who came into the game as defensive replacements in the seventh.
Landon Powell -- who entered as a pinch-hitter in the eighth -- brought two more runners home with a double to right-center in the ninth. Barton then doubled, and a throwing error by Ryan Spilborghs allowed Powell to score and moved Barton to third -- all with none away.
Huston Street then came in, looking to stop the bleeding and close the door on his former team.
Street got Hannahan to pop out, but Crosby brought Barton home with a sac fly to bring the A's within two. Street sent Rajai Davis down swinging to save the day for the Rockies.
"I was trying to give guys a couple innings off with us down nine," Geren said. "I wanted some guys to get some rest, others to get some at-bats. [The bench players] took advantage of their opportunities."
After pitching like a 10-year veteran his last time out, throwing seven innings of one-run ball, Trevor Cahill let his youth show Saturday.
Colorado tagged Cahill, 21, for four home runs. He gave up seven runs on eight hits, needing 82 pitches to get through 3 2/3 innings.
It's the first time an Oakland pitcher has allowed four home runs in a game since Barry Zito was dealt the same hand in a 14-0 loss to Texas on Aug. 9, 2006.
"His sinker wasn't really getting down in the zone," Geren said of Cahill. "He had less movement on his pitches, he was getting behind in counts, he didn't have that great of command tonight."
Colorado starter Jorge De La Rosa entered the game with a 5.85 ERA, having allowed 11 runs in his past two starts. You wouldn't have known it, as he held the A's in check early by pitching six innings of five-hit ball to improve to 4-7.
Kennedy slid over to third base in the eighth inning, fielding the position as a Major Leaguer for the first time.
"That's something I've been thinking about doing for a while," Geren said."
With slick-fielding Mark Ellis set to come off the disabled list and return to his usual second base position, Geren said Kennedy would start at third or first base Sunday.
Only one ball went Kennedy's way at third -- a frozen rope hit by Garrett Atkins that got by for a single.
Garciaparra batted cleanup in his first start since coming off the DL on June 12 (strained right calf), going 1-for-3 as the designated hitter.
Adam Loberstein is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.