Not only was he facing one of the top teams in the American League in consecutive starts, but he was facing the other team's top pitcher, as well.
Last Tuesday, Haren had the task of facing the defending American League champs, the Tigers, and ace Justin Verlander. On Sunday, he was on the hill against the AL West-leading Angels and their top pitcher, John Lackey.
Haren was able to beat Verlander and the Tigers and was in line to get the win on Sunday, but had to settle for a no-decision after the Angels rallied off the A's bullpen for a 4-3 win and salvaged a split in the four-game series.
The A's went 4-3 over the seven-game homestand, doing so against two of the top teams in the AL.
"Overall, it was a good homestand," A's manager Bob Geren said.
Down 2-1 in the bottom of the sixth, Jack Cust started the inning with a single, and two batters later Dan Johnson unloaded a home run to left-center to gave the A's a 3-2 lead. That put Haren in line to pick up his 14th win.
It was Johnson's 11th home run of the season and his first since July 2 against Toronto.
The Angels rallied in the top of the seventh, scoring two runs off A's reliever Kiko Calero, who exited the game with an ERA of 5.97, and Andrew Brown.
"There were tough breaks," Geren said. "It's a game where [Calero will] get the loss, but he actually pitched well."
Geren said that he felt there weren't too many hard hit balls off his reliever and a few balls found holes. Haren felt he needed to go deeper into the game, but was relegated to six innings after 113 pitches.
"They worked me pretty well," Haren said. "I need to be able to go seven or eight innings. I need to go deep into games."
Both Haren and Lackey came in with 13 wins, and Lackey was able to leave with his 14th, taking advantage of the Halos' seventh-inning rally.
Haren left still leading the AL in ERA at 2.46 after going six innings, allowing two runs and striking out six.
"He did another fine job," Geren said of Haren. "He pitched well enough to win."
Each Angels rally was centered around a walk issued to Vladimir Guerrero, which begs the question of what to do with the Angels slugger.
He hit four home runs in the first two games, and then in Sunday's contest, the first three Angels runs came in innings in which he was walked.
"It's kind of a pick your poison," Haren said. "You can't let Vlad beat us, and Garret [Anderson] hits me pretty well. It's a tough 3-4 in the lineup. I was trying to do what was best for the team."
In the first inning, Guerrero was walked with two outs and nobody on. He wound up scoring on a triple by Anderson that just got by a lunging Travis Buck in right field.
In the fifth inning, Orlando Cabrera laid down a two-out bunt single, which was followed by a walk to Guerrero. Anderson, once again, came through with an RBI hit.
"They're both good hitters," Geren said. "They're 3-4 Major League hitters. You always try to look to see who's hot at the time."
In that seventh inning against Calero, Guerrero was walked after a single by Chone Figgins and a bloop double by Cabrera. Anderson drove in his third run of the game with a sac fly before Casey Kotchman's two-out hit gave the Angels the lead.
Each A's rally started with a single by Cust, as he had a base hit in the second and scored on a double-play grounder by Marco Scutaro.
The A's had the bases loaded that inning with nobody out, but got only one run. They loaded the bases in the third inning again, but got nothing across.
"It was a game of missed opportunities," Geren said. "We weren't able to deliver a big blow."
Matt Smith is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.