The Padres are a game below .500, but remain atop the West by four games— the latest in a season any division leader has had a losing record.
Peavy has been steady all year for San Diego, leading the team with a 3.14 ERA. The 24-year-old right-hander is 2-1 with 38 strikeouts and a 2.03 ERA over his last four starts.
Peavy, who leads the NL with 174 strikeouts, has pitched well against Florida, going 2-1 with a 2.18 ERA in three career starts.
Beckett has recovered from several nagging injuries to go 3-0 with a 3.20 ERA in five starts since coming off the disabled list. The hard-throwing righty went the distance Saturday, allowing one run and striking out seven to earn a 2-1 win over the San Francisco Giants.
He’s 8-2 with a 2.59 ERA in 11 starts at home this season.
The Marlins have won nine of their last 11 home meetings with the Padres, including Wednesday’s 6-0 victory. Dontrelle Willis pitched a five-hitter and added a two-run double to lead Florida.
San Diego did not have a runner reach second base until Damian Jackson doubled with one out in the ninth.
“He’s as good as anybody,” San Diego manager Bruce Bochy said of Willis. “We aren’t the first team he has shut out this year.”
The Marlins trail NL wild card leaders Houston and Philadelphia by 1 1/2 games.
Florida had five extra-base hits in the first two innings even without second baseman Luis Castillo, who is sidelined with a sore hamstring. Outfielder Miguel Cabrera also got the day off Wednesday as he is mired in a 7-for-36 slump with one home run over the last 10 games, lowering his average from .355 to .342.