Pittsburgh loses third in a row

ST. LOUIS — Luke Weaver pitched shutout ball into the sixth inning and also drove in a run Friday night, helping the St. Louis Cardinals improve their postseason hopes with a 4-1 win over the Pittsburgh Pirates.

The Cardinals have won seven of nine, pulling within four games of the NL Central-leading Cubs. St. Louis is even closer in the chase for the second wild-card spot.

The Pirates have lost three in a row.

Weaver (5-1) has won four straight decisions, not allowing more than two runs in any of them. He gave up seven hits, walked none and struck out seven in 5ª innings.

Weaver drove in the Cardinals’ first run with a broken-bat groundout and scored a run.

Juan Nicasio made his St. Louis debut and got four outs for his third save. The Cardinals got him from Philadelphia for a minor leaguer earlier in the week.

Nicasio pitched most of the season with Pittsburgh before being plucked off waivers by the Phillies in late August. He spent just six days with the Phillies, appearing in two games.

Trevor Williams (6-8) allowed four runs in 4ª innings.

The Cardinals returned home in the early-morning hours after going 7-3 on a road trip that finished in San Diego. The Pirates began a nine-game swing after going 4-3 at home to start September.

Williams gave up runs in the third and fourth, and a two-run single in the fifth to Jose Martinez.

Pinch-hitter Adam Frazier singled in the seventh for Pittsburgh’s run.

Trainer’s room

Cardinals: 2B Kolten Wong (sore back) is expected to be back in the lineup tonight. Manager Mike Matheny said he thought Wong would be available to pinch hit. … 3B Matt Carpenter (right shoulder strain) returned to the lineup and hit leadoff.

Pirates: OF Gregory Polanco and Frazier were both reinstated from the disabled list for Friday’s game. Polanco batted third and played right field.

On deck

Tonight: Pittsburgh Pirates at St. Louis Cardinals, 7:15 p.m.

Pitching matchup: Pirates RHP Chad Kuhl (7-10) vs. Cardinals RHP Carlos Martinez (11-10)

TV: AT&T Sports Network