"But don't count me out for the year, I guess," Peavy said.
Manager Bruce Bochy and general manager Kevin Towers said they weren't sure when the 24-year-old Peavy sustained the injury and certainly weren't aware about the severity of it when he started Tuesday's game, the Padres' first in the postseason since the 1998 World Series.
"It's a big blow to lose a pitcher of his stature at this point of the season, no question," Bochy said. "It shows what kind of gamer he was that he went out there to throw in that kind of pain."
Peavy said he first sustained the injury during last Wednesday night's celebration at PETCO Park after the Padres clinched the NL West title with a win against the Giants. It happened in the initial scrum when the Padres players ran toward Trevor Hoffman, who closed the game, on the mound.
"We were jumping around on the field," Peavy said. "The next day I thought I had some bruised ribs, that I caught an elbow or something. But I never would've imagined it would have been this."
Peavy was treated last week for the injury by Padres head trainer Todd Hutcheson, but he did his regular work on the side and figured he would be fine to pitch in the game.
"We thought it was unlikely that he had fractured a rib," Hutcheson said. "We didn't even X-ray it."
Evidently, though, Peavy didn't tell anyone how badly he felt until he came out of the game, went into the training room and confided in Hutcheson, "My ribs are killing me."
"We didn't find out about it until after the game," Bochy said. "He didn't tell us, and I don't think he was smart about it. It's hard to pitch with that kind of [injury]. We would have pinch-hit for him early if we would've known, but he didn't let me or [pitching coach] Darren Balsley know. We had no inclination that there was something wrong. That was Jake being competitive, but we certainly would've liked to have known about it."
Peavy allowed eight runs on eight hits, including the grand slam and a first inning solo shot to Jim Edmonds. He left with a 16.62 ERA for 4 1/3 innings as compared to his 2.88 ERA during a 13-7 regular season. Peavy, who had shoulder problems last month, hadn't pitched in eight days.
"I know that Darren did know," Peavy said when asked about who knew what when. "I think the surprise was that the injury was a little more severe than we thought. I didn't think I was being selfish staying in the game. I thought I was capable of making my pitches."
But while throwing to Larry Walker during the third inning with the bases jammed, Peavy caught his spike in the dirt as he came down on his delivery and nearly tumbled to the ground. The 55-foot changeup skipped past catcher Ramon Hernandez, with the Cardinals' second run of the day scoring on the wild pitch.
Bochy and Balsley said Peavy sustained the injury well before that incident, although Peavy noted that it began to feel worse at that juncture. Peavy said he hit his ribs on his thigh as he stumbled off the mound.
"The longer I tried to stay out there, the worse it got," Peavy said. "I hit it in the third on something freaky like that. I knew it was pretty bad when I came out of the game. I was having trouble breathing. I was having trouble throwing the fastball."
Earlier in the game, the right-hander showed no evidence of a problem. During the opening two innings, 18 of Peavy's first 20 pitches were strikes.
"Jake has a tendency to catch his spike in the dirt when the mound is high and flat," Balsley said. "He does it sometimes when he pitches on the side. But I don't think that had anything to do with it."
The probable loss of Peavy for the playoffs is complicated by the fact that the Padres decided to go with a 10-man pitching staff, at least for this series. Peavy could ultimately be replaced in the rotation by Brian Lawrence, who was relegated to a long-relief role, but he can't be replaced on the 25-man roster. Veteran right-hander Chan Ho Park was left off in lieu of third baseman Sean Burroughs.
But Hutcheson said a lot of it will depend on how fast Peavy can recover.
"It's a broken rib," Peavy said. "Maybe there are a lot of things we can do to make it feel a lot better. I'm going to take a few days off and maybe look at some of those options. We'll see how they make me feel. We're going to do everything we can do. Whether it does, I don't know."
But Bochy is obviously planning for the rest of this series, at least, without Peavy.
Bochy said Adam Eaton would now start Game 4 on Sunday in San Diego, if the series goes that far. He will reserve any decision about a pitcher for Game 5, if necessary, on Monday in St. Louis.
"Let's get there first and we'll worry about that later," Bochy said. "But it was bad news [already] today not to have [Peavy] at 100 percent. He couldn't have been any more rested for this to have come up. He's had a few [shoulder] injuries during the season, but for this to happen now, it couldn't be worse news."