OAKLAND -- Anibal Sanchez always had great stuff. Then again, a lot of pitchers in the big leagues have great stuff and but never translate that into the sort of success their talent suggests.

ALDS

As the 2012 Trading Deadline approached, the 28-year-old Sanchez seemed to be on that career arc. Sure, he had pitched a no-hitter as a Marlins rookie in 2006. But now he was approaching baseball middle age and had a mediocre 44-45 lifetime record and a so-so 3.75 ERA when he was acquired by the Tigers.

Sometime between then and now, though, something clicked. When he takes the mound at Comerica Park in Game 3 of the American League Division Series against the Athletics on Monday afternoon (1 ET, MLB Network), it will be as the reigning AL ERA king. And, yes, it says something about Detroit's rotation depth that a guy with a 2.57 ERA is slotted behind both Max Scherzer and Justin Verlander at the most critical time of the year.

The thing is, it's difficult for the Tigers to explain what's changed being that they didn't see him regularly when he was pitching in the other league. Pitching coach Jeff Jones tweaked his mechanics. But even Jones can't fully explain the transformation.

Tale of the Tape: Game 3
Anibal Sanchez
Tigers
Jarrod Parker
Athletics
2013 regular season
Overall: 14-8, 2.57 ERA, 54 BB, 202 K Overall: 12-8, 3.97 ERA, 63 BB, 134 K
Key stat: Sanchez has been dominant in the postseason. He went 1-2 with a 1.77 ERA and 0.98 WHIP last year. Key stat: Parker was riding a 19-game unbeaten streak until mid-September, holding a 9-0 record with a 2.61 ERA.
At Comerica Park (reg. season)
2013: 8-3, 2.70 ERA
Career: 11-5, 2.92 ERA
2013: N/A
Career: N/A
Against this opponent (reg. season)
2013: 1-0, 3.75 ERA
Career: 1-1, 5.09 ERA
2013: 0-1, 21.60 ERA
Career: 0-2, 10.00 ERA
Loves to face: Josh Reddick, 0-for-9, 2 K
Hates to face:: Seth Smith, 7-for-19, 3 HR
Loves to face: Prince Fielder, 1-for-10, 2 K
Hates to face:: Austin Jackson, 6-for-11, HR
Game Breakdown
Why he'll win: Sanchez led the AL with a 2.57 ERA and went 7-2 with a 2.20 ERA in the second half. Why he'll win: Parker has pitched well on the road this season, posting a 3.74 ERA and striking out 64 in 86 2/3 innings.
Pitcher beware: Sanchez gave up four runs in five innings to the A's on Aug. 26, throwing 112 pitches. Pitcher beware: Parker struggled at the end of the season, giving up at least seven runs in two of his last three starts.
Bottom line: Sanchez only allowed nine home runs this season, and will need to continue that trend against a powerful A's lineup. Bottom line: Parker needs to find a good game plan against Detroit. He went 0-2 with a 4.26 ERA in last year's ALDS against the Tigers.

"When he got here last year he struggled a little bit [1-3, 7.97 ERA in his first four starts]," Jones said. "And I think he got to where he became unafraid to throw any pitch at any time. There's something to be said for that, obviously, because the hitter never really knows what's coming. And he stays out of patterns. To me, that's been the biggest difference compared to when he got here.

"He's got four quality pitches. His velocity is good. He's got great movement and he's got a lot of confidence. The guy competes as well as anybody I've ever coached. He's fun to watch."

It was the arsenal and the velocity and maybe even the inner fire that convinced Dave Dombrowski to package Jacob Turner, Brian Flynn and Rob Brantly to Miami for Sanchez and second baseman Omar Infante. But even the Tigers president and general manager couldn't have predicted the way Sanchez has blossomed.

"We were looking for a guy who would fit into at least a No. 3 role for us. And our scouts felt he could do that. We had a couple guys, primarily, who had seen him. Mike Russell had seen him a lot and Scott Reid had watched him a lot, and they thought he would fit into that type of description," Dombrowski said.

"We knew he was a free agent at the end of the year and [that was why] he had the potential to be traded. They recommended him. They thought he would pitch well for us. To say that [we knew] he would pitch as well as he has would be inaccurate. But we did think he was a guy who could win 15 games in the big leagues. ... We really had thought when we acquired him it was most likely going to be a very short-term situation. But, as it developed, we decide to keep him long term, and we're fortunate that we did."

After that slow start, Sanchez got on a roll. In his last eight regular-season appearances, his ERA was 2.15. In three postseason starts, it was 1.77. The Tigers locked him up with a 5-year, $80 million deal. Some free agents have a difficult transition after signing for big bucks. Sanchez flourished. He won a career-high 14 games and probably would have been right in the middle of the AL Cy Young conversation if he hadn't missed three weeks with a right shoulder strain.

The way this ALDS has unfolded, with the teams splitting the first two games in Oakland, Sanchez will start what becomes the Tigers' most important game of the season to date. The team that loses Monday will be one loss from elimination.

"In that situation, the short series, it's a challenge," Sanchez said during Sunday's media availability at Comerica Park. "You have to win. You don't have to think about it. If we are ahead, 2-1, 2-0, I think we need to win it. Win games and make another series. I always say in playoffs, it's day by day. We don't need to think about the whole series."

"This is a challenging game. We need it here. We need this win. We need to hang onto that situation, because if we're ahead, we're going to feel more comfortable for the next game. So we need to come early and try to get some runs, and I'm going to do the best I can, try to be aggressive from the beginning."

As it turns out, a pitcher who arrived as something of a question mark has evolved into an exclamation point that the Tigers will be counting on heavily Monday.

"To be honest with you, I knew nothing about him at all [when he came to Detroit]," manager Jim Leyland said. "I think I saw him one time in Spring Training. I knew nothing about him, but our scouts were high on him.

"When we first got him, he looked fine but really didn't look out of the ordinary too much. Then as the season went on, I mean, he's got good stuff, throws the ball harder than I thought he would throw it. He has a repertoire of pitches. He can throw anything on any count. I think this guy has some of the better stuff in the American League, in my opinion. He's been terrific for us."

Better than anybody could have anticipated, in fact, even if it's hard to pinpoint exactly why.