ST. LOUIS - The St. Louis Cardinals absorbed a blowout defeat that cost them a chance for a four-game sweep of the Pittsburgh Pirates Thursday night.

And the 9-1 setback at the Pirates' hands at sold-out Busch Stadium was not even the Cardinals' worst loss of the day.

Earlier, St. Louis disclosed that All-Star catcher Yadier Molina would sit out 8-12 weeks due to a torn ligament in his right thumb. Molina, who suffered the injury while sliding into third base Wednesday night in the second inning, will undergo surgery on Friday.

The Cardinals (50-43) missed Molina across the board in this one, although his presence might not have mattered. Pittsburgh starter Edinson Volquez went the distance, scattering six hits, walking two and fanning five as he improved to 8-6 with his fourth straight win.

The Pirates (48-44) got two RBIs apiece from left fielder Josh Harrison, center fielder Andrew McCutchen, second baseman Neil Walker and catcher Russell Martin as they pulled within 3 1/2 games of first-place Milwaukee in the National League Central.

Martin went 3-for-5, capping the scoring with a solo homer in the ninth. Harrison's two-run double in the sixth off reliever Tyler Lyons gave Pittsburgh a 6-1 lead, essentially ending the game's competitive phase.

Shelby Miller (7-8) took his third straight loss, allowing five hits, four runs and four walks over five innings while striking out only one. It was his fourth straight outing of less than six innings.

St. Louis stayed two games behind Milwaukee, which it visits this weekend for a three-game series.

Pittsburgh broke on top for the first time in the series when Martin's two-out single in the first scored McCutchen. It was the 500th career RBI for Martin.

St. Louis evened the score in the third on a sacrifice fly to center field by third baseman Matt Carpenter, plating Kolten Wong. The Cardinals second baseman led off with a bunt single, stole second and moved to third on a sacrifice bunt by Miller.

McCutchen's two-out RBI single in the fifth snapped the 1-1 tie. Second baseman Neil Walker followed with a two-run double just over the outstretched glove of right fielder Oscar Taveras, extending his hitting streak to 12 games.

NOTES: St. Louis called up C Audry Perez from Triple-A Memphis to serve as a backup to Tony Cruz while All-Star C Yadier Molina is sidelined. Perez hit .288 with two homers and 21 RBIs in 44 games at Memphis, throwing out 29 percent of base-stealers. ... Pittsburgh recalled OF Jaff Decker from Triple-A, optioning RHP Brandon Cumpton to Indianapolis. Decker was hitting .266 with four home runs and 29 RBIs in 71 games for Indianapolis. He is in his second stint major league stint this year. ... The Cardinals handed Pittsburgh its first road series loss since May. The Pirates had won five consecutive road series, their best streak of success away from home in 32 years.