MILWAUKEE -- Plan B for reaching the postseason might be better than Plan A for the San Diego Padres. In fact, it will have to be better.

Had the Padres won either Saturday or Sunday against the Milwaukee Brewers at Miller Park, they would have secured the National League Wild Card berth. But they won neither game, losing, 11-6, on Sunday in what normally would have been the regular-season finale.

Now the Padres must go to Colorado on Monday for a one-game Wild Card tiebreaker. The Rockies climbed into a tie with the Padres with a victory over the Arizona Diamondbacks.

Ordinarily, this would be an extremely deflating set of circumstances for any team, losing a clear cut postseason berth on the last day of the season. The Padres' performance on Sunday seemed completely atypical, including ineffective relief pitching and defensive breakdowns.

The Padres left the field not knowing their postseason fate, not knowing if they were going to Colorado for the tiebreaker playoff game or to Philadelphia for a Division Series. They entered the Miller Park visitors' clubhouse with Colorado leading Arizona, 4-1, and they watched quietly on the clubhouse televisions, as Arizona came back in the top of ninth, but eventually fell, 4-3.

So the tiebreaker playoff it is for the Padres. But the Padres always had a contingency plan for a Wild Card tie. That plan can be summed up in two words: Jake Peavy.

Peavy, not only the ace of the Padres' staff, but also a very likely Cy Young Award winner, could have pitched on Sunday, but that would have been on short rest. He last pitched on Wednesday.

By keeping him out of Sunday's start, the Padres may have reduced their chances of winning that game. But they increased their chances of winning their next game. Under the best-case scenario, Peavy would have opened a National League Division Series for the Padres. But given the way things developed, or didn't develop, this weekend, the Padres will have Peavy starting on full rest in the tiebreaker against the Rockies.

The start on Sunday went to Brett Tomko, picked up on Sept. 4 after being jettisoned by the Dodgers. His overall numbers for the season are not good, but the Padres had won all three of the games he had started for them. Here, he was unable to hold either a 3-0 lead or a 4-2 lead.

But the Padres decided to save Peavy for what could be the last game of the season. Decisions of this sort are always debatable, but the Padres have chosen a path in which their best starting pitcher becomes their last line of defense. This is not an extremely radical approach to their circumstances, and it is hard to argue with saving your best pitcher for the one make-or-break game.

"We had this mapped out for a while, that it could come to this, because of what was happening over the past couple of weeks," manager Bud Black said. "We feel good about Jake, obviously, with the way he's been throwing, on regular rest.

"Jake will be ready. He knew it could come to this."

Confidence in Jake Peavy is widely shared, and why not? He is winning the pitching triple crown; leading the NL in victories, earned run average and strikeouts.

"It's a one-game season, and we'll have our ace out there," said outfielder Brian Giles. "I like our chances."

Even more to the point, Peavy himself seems to relish this situation.

"I didn't want it to come down to this, but it has," he said. "But it's going to be fun. Our playoffs are starting with Game 7. I'm excited about the opportunity, the challenge that tomorrow will bring."

This sort of thing, Peavy said, was "why we play the game." You could clearly understand that. Still, the reason the Padres have to play this 163rd game of the regular season is because they couldn't win No. 161 or No. 162.

That was disappointing. But as fallback positions go, having Jake Peavy rested, ready and eager to start the biggest game of the year seems to offer not only considerable consolation but also considerable promise.