From the perspective of an old-school, hardcore hardball guy like Bruce Bochy, it just doesn't get any better than Tuesday night's marquee matchup at PETCO Park.

"You've got one of the up-and-coming stars against one of the greatest pitchers of all time," Bochy said of the showdown between the Padres' 24-year-old gunslinger and the Astros' masterful Rocket, as lethal as ever at age 43.

Clemens and Peavy have a friendly relationship, traced to a tour of Japan with Bochy over the winter, but there will be nothing friendly about this competition. There are few athletes as fiercely competitive in Major League Baseball as these two power pitchers with uncommon control.

"Both of them have a maniacal focus on the mound on every pitch," Bochy said. "No mental lapses out there. I look forward to them hitting against each other."

Both Clemens and Peavy are coming off performances that might have left a bitter aftertaste, adding another element to the confrontation.

Clemens, ninth all-time with 339 career wins and leading the Major Leagues with his 1.53 ERA, gave up five runs and five hits in 6 1/3 innings against the Brewers at home, his record falling to 11-5.

Peavy allowed two runs in six innings in a 2-0 loss at Florida, giving him consecutive defeats. He'd been beaten by the Phillies, 3-2, at PETCO Park on a three-run first-inning homer by Pat Burrell.

Peavy was fuming after the Marlins prevailed with RBI singles by the No. 8 and No. 9 hitters, with Josh Beckett shutting down the Padres with two innings of relief help.

"I'm sick of losing, man," said Peavy, who is 10-6 with a 3.14 ERA.

This will be Peavy's 101st career start. Clemens, apparently clear of lower back pain reported after the loss to the Brewers, is making the 665th start of his Hall of Fame career.

"It's pretty incredible when you think about it," Bochy said. "This could be right up there with his best seasons."

Clemens leads the National League in opponents batting average against (.187) and road ERA (0.37), as well as overall ERA. He's fifth in strikeouts with 155 -- 28 behind Peavy, the league leader.

Peavy also leads in strikeouts per nine innings (10.3) and is fifth in batting average against (.216).

"I hope everybody's looking forward to it," old-school guy Bochy said. "I know I am."

Eaton status pending: Bochy withheld for another day a decision on whether to activate Adam Eaton for a start on Friday against the Rockies or return him to Triple-A Portland for a fourth rehab start.

Eaton threw 73 pitches in his most recent start on Saturday, giving up seven hits and two runs across four innings. He went to the bullpen afterward and threw 20 more pitches.

Eaton, who hasn't started for the Padres since straining the tendon in his right middle finger on June 15, was 9-2 with a 3.45 ERA when he lost the ability to throw breaking balls. When he reclaims his spot in the rotation, someone will be the odd man out.

Bochy refused to tip his hand. But with Pedro Astacio coming off three consecutive solid efforts as the designated Saturday starter, one of the following -- Chan Ho Park, Woody Williams or Brian Lawrence -- is the likely candidate to go to long relief.

"We'll have to finagle the rotation a little bit to decide which way we're going to go," Bochy said.

Nady stays in lineup: With five hits in the three games in Atlanta, including his first career grand slam and a double against John Smoltz, Xavier Nady earned the start at first base on Monday night against another accomplished right-hander, Roy Oswalt.

It wasn't an easy decision for Bochy, given that left-handed hitting Mark Sweeney and Robert Fick also have been productive.

"They're all swinging well," Bochy said. "Nady's been getting some good at-bats -- and he's had some big hits, too." Nady, through Sunday, had 13 homers and 41 RBIs in 256 at-bats, less than half a full season's worth.

Greene coming along: Khalil Greene was in the clubhouse to greet his teammates while recovering from the fracture in his left big toe. The shortstop praised the play of Damian Jackson in his stead on the road trip, and said he was pointing toward mid-September for a return.

"I'm doing what I can, but I'm fairly limited right now," Greene said. "I'm always optimistic. I plan to be back. But D.J. can get the job done. He's been incredibly valuable for us all year."

On deck: Peavy (10-6, 3.14 ERA) vs. Clemens (11-5, 1.53 ERA) on Tuesday night at PETCO Park. A potential classic.