OAKLAND -- Jarrod Parker knew he was heading into a favorable situation when he was traded last December to the A's, an organization known for turning young starting pitchers into stars.

Parker couldn't have predicted that transition would end up with him pitching in a decisive Game 5 in the American League Division Series. Then again, very few experts would have made that call about the A's in December, either.

But that's what Parker and the A's have in front of them Thursday, when they host the Tigers for the right to advance to the AL Championship Series.

A's vs. Tigers

For the 23-year-old right-hander, who was enjoying the wild celebration in the A's clubhouse after their thrilling Game 4 victory, Thursday's outing will be the toughest test of his career, one that he'll tackle with the same approach that has worked well all year.

"One thing we're doing really well right now is preparing each and every day like it's our last, just taking it one at a time," Parker said.

This is that very kind of day, and Parker's ready to take the ball.

Tale of the Tape: Game 5
Justin Verlander
Tigers
Jarrod Parker
Athletics
2012 Regular Season
Overall: 33 GS, 17-8, 2.64 ERA, 60 BB, 239 K Overall: 29 GS, 13-8, 3,47 ERA, 63 BB, 140 K
Key stat: Held the A's to one run on three hits in seven innings in Game 1 Key stat: Gave up two earned runs in 6 1/3 innings in Game 1
At Oakland Coliseum
2012: 1 GS, 1-0, 1.29 ERA
Career: 9 GS, 4-4, 2.47 ERA
2012: 15 GS, 6-5, 2.61 ERA
Career: 15 GS, 6-5, 2.61 ERA
Against this opponent
2012: 2 GS, 2-0, 0.69 ERA
Career: 13 GS, 7-5, 2.38 ERA
2012: 1 GS, 0-1, 3.18 ERA
Career: 1 GS, 0-1, 3.18 ERA
Loves to face: Cliff Pennington, 0-for-13, 5 K
Hates to face: Coco Crisp, 8-for-22, 2 2B, 3 RBIs
Loves to face: Prince Fielder, 0-for-6
Hates to face: Miguel Cabrera, 2-for-5
Game breakdown
Why he'll win: Has allowed two runs in 20 innings vs. Oakland this season Why he'll win: A's stole all the momentum with Wednesday's walk-off win
Pitcher beware: Has a 3.57 road ERA this year compared to 1.65 ERA at home Pitcher beware: Hss made one postseason start and never started a do-or-die game
Bottom line: Pop the champagne and move on to the ALCS Bottom line: It's improbable, but not impossible

To think, a year ago this scenario would have been impossible to fathom for Parker. A year ago, Parker was just off making his Major League debut and making a brief playoff appearance with the D-backs, the team that made him a first-round pick in 2007.

"I was glad that I got an opportunity and that the A's wanted me enough to make a big deal for me," said Parker, acquired along with reliever Ryan Cook and two others for starter Trevor Cahill. "And I think to be able to come to an organization that's known for getting guys ready and prepared as much as they can, and they do a great job with pitchers, I couldn't be happier where I'm at right now and the place we're at.

"We're in the playoffs and I think that's what's exciting for us as a group and myself, as well."

It's about to get a lot more exciting for Parker. For the second time in five days, he'll be facing Tigers ace Justin Verlander, who got the win in Game 1 despite a strong first postseason effort by Parker.

Parker allowed two earned runs on seven hits in 6 1/3 innings but was tagged with the loss in a 3-1 Detroit victory in the opener of the ALDS.

A's manager Bob Melvin expects Parker to use what he learned from that start and turn it into an even better outing in Game 5.

"I think any time you get experience your first time in the postseason, now all of a sudden the next time out you know what to expect and know you can handle it," Melvin said. "His season as a whole, you've seen him get better and better and better and handle some things. Whether it's getting a few guys on base and getting his pitch count up earlier in games, being able to combat that and work past that, you know, as the season goes along, he's just gotten better and better."

It didn't exactly start off the way Parker, or the A's for that matter, expected when they acquired the former No. 1 draft pick (No. 9 overall in 2007) from the D-backs.

After a rough Spring Training, Parker started off the season in Triple-A Sacramento. But after he went 1-0 with a 2.18 ERA in his first four starts, he was recalled April 25 and never looked back, going 13-8 with a 3.47 ERA -- his 13 wins the most by an A's rookie since Harry Byrd won 15 for the 1952 Philadelphia A's.

"I think early on in spring I was trying to do too much," Parker said. "When I went to Triple-A, it was kind of a blessing to be able to hone in on some things and slow it down, and get right and be able to come back to the big leagues and be ready with 100 percent effort and be kind of fine-tuned with my mechanics and just basically be as ready as I can, and not have to work on something at this level.

"You want to be as ready as you can and take what you've done your whole career and put it into each and every game."

This particular game is unlike any other Parker has pitched before. It's the postseason, and he's facing perhaps the best pitcher in the Majors with his team's season on the line.

"It's going to be fun. I think it's what makes this time of year great," Parker said.