With the A's in a 3-0 hole and facing elimination, Haren will get the start in Game 4 of the American League Championship Series on Saturday, which is a day later than he originally expected.
"[I was] a little surprised," said Haren. "I was told I had Game 3. The same kind of thing happened, though, in the Minnesota series. I was told either three or four, and I got Game 3 in that series. ... I had a feeling that if [Rich] Harden went out and threw OK in the Instructional League and his arm felt OK, they'd want to make sure to get him two starts."
Instead of looking at the extra day as some sort of slight, Haren is just eager to take the ball and help his team get this series headed back in the right direction.
"Of course I'd like to have two starts, but I assured them if something went wrong with Rich that I'd be ready for Game 7 anyway," Haren said. "I think it's a safer way to approach it. It's been a long time for Rich. He had such a long road to recovery and he sat out for so long, and I think that he deserves this start."
One thing Haren won't have to worry about heading into Game 4 against the Tigers is fatigue. He'll make this start after seven days of rest.
"I don't see that being a problem," said A's manager Ken Macha. "You know, he's got plenty of work on the side. He came out here [Thursday], chipped off the ice and made some pitches in the bullpen. I think he'll be fine."
The ice Macha was speaking of was both literal and figurative. The temperature for Haren's start is supposed to hover in the mid-40s.
"The coldest I ever pitched in was in [Class A] Peoria, Ill.," said Haren. "My first start in [Class A] was there. It was 18 [degrees] and it was snowing during the game, and there was about five or six people in the stands, one of them being my dad. That was probably the coldest I've pitched in. I think the advantage probably goes to pitchers being able to maybe throw inside a little more and keeping the hitters honest, keeping them uncomfortable."
At a time of year when many pitchers are going on fumes, Haren thinks the extra layoff since his last outing can be a bonus, as long as he doesn't get too caught up in the moment.
"My arm is going to feel great when I go out there, probably too good," Haren said. "I've got to concentrate on keeping the ball down, and I'm sure the energy in the park is going to be great and the atmosphere will be great. I think it's going to be about controlling my emotions. My arm is going to feel great, I know that just from the bullpen [Thursday]."
As Haren's 14-13 record this season shows, he's had his ups and downs.
"This is the second year he's started in the Major Leagues, and he's still learning his delivery and how to stay in it, and how to make his pitches," Macha said. "This is another young guy learning how to pitch in the Major Leagues. He also has a bunch of upsides. Generally speaking, when you talk about young pitchers, you always talk about the ups and downs that they have, and he's not any different than any of the other ones."
But the 26-year-old Haren has experience on the big stage. He pitched out of the bullpen for the Cardinals in the 2004 World Series, holding the Red Sox -- who swept St. Louis in four games -- scoreless over 4 2/3 innings.
He acknowledges that it's different to be a starter for a postseason team.
"Going into my last start even, I was still extremely nervous, anxious, all those things," Haren said before Game 3 on Friday. "I think it helped me a little bit just having been out there before. And I think, going into [Saturday], it's going to be a tough situation for us, because obviously it's going to be ... 3-0, and it's going to be pretty much a must-win for us."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.