CHICAGO • With the rain pouring Sunday morning in Cincinnati, a delay imminent, and a postponement possible, Cardinals manager Mike Matheny sat in his office and juggled interviews. In between radio shows he explained some of the reasons he wouldn’t let clubhouse meteorologists lull him or, he hoped, the team into thinking a game wouldn’t happen.

He wanted preparation to go on as normal and the starting pitcher to go through his pregame ritual as usual. Then there was the biggest reason Matheny said he wanted to play the game.

He likes the way his team is playing.

“One hundred percent,” he said.

The rain cleared after nearly three hours of waiting, and the Cardinals completed a four-game sweep. Against the rudderless Reds, the Cardinals found their footing and their first winning streak of the season, but they couldn’t outrun the weather forever.

Temperatures around freezing, snow, and forecasts for biting wind chills led the Cubs and Major League Baseball to postpone Monday night’s scheduled game at Wrigley Field. The Cubs cited “inclement weather” and “wind chills in the 20s” as their reasoning for pushing the game back until July 21, in a day-night doubleheader. The teams are set to resume play Tuesday night, with a series finale set for Wednesday.

The Cardinals added reinforcements shortly before the postponement, bringing infielder Jedd Gyorko and reliever Luke Gregerson back from Florida and the disabled list.

To make room on the infield for third baseman Gyorko (hamstring), the Cardinals optioned Yairo Munoz to Class AAA Memphis. Gregerson (hamstring), who spent the past two weeks with Class A Palm Beach on a rehab assignment, nudged Mike Mayers from the bullpen. They join a team on a hot streak about to revisit a ballpark that had a chilling effect on their postseason aspirations. Last year, Wrigley is where the Cardinals’ ability to contend was confined.

In nine games at Wrigley, the Cardinals went 1-8 last season, their worst record on the North Side since 1918. They squandered eight leads in those eight losses. The Cardinals scored nine runs in one inning at Wrigley.

The Cubs outscored them 43-24 in the other 80.

It is where the Cardinals slipped out of contention for the division title and a wild card. The Cardinals had 14 losses to their archrivals last season, the most losses to the Cubs of any team in the National League Central. The Cardinals pitched OK against the Cubs — their 4.31 ERA was second-best to second-place Milwaukee’s 4.00 — but the offense froze. The 66 runs the Cardinals scored against the Cubs were the fewest in the division. By 13. They hit .213 in those 19 games, while the Cubs averaged 4.42 runs a game.

The fallout from the issues the Cardinals had, head to head, against the Cubs was obvious in their records. Subtract their 5-14 record against the Cubs, and the Cardinals went 78-65 against the rest of baseball.

Against teams that weren’t the Cardinals, the Cubs went 78-65.

The nine games the Cardinals finished behind the division-winning Cubs were nine games they lost to the Cubs. Eight came at Wrigley.

Given the unplanned off day Monday, the Cardinals initially announced they would keep their pitching assignments as scheduled. That shifted later in the day. Rather than start Adam Wainwright on Tuesday and Michael Wacha on Wednesday — in their announced order — the Cardinals decided to keep Luke Weaver in the Cubs series. He’ll start in Wacha’s place Wednesday. Wacha will move to Friday, when he’ll face the Cincinnati Reds at Busch Stadium. Wacha is 9-1 in his career with a 2.99 ERA in 17 games (15 starts) against the Reds, and he got the win this past Thursday with five innings vs. Cincy.

Weaver has been the Cardinals most consistent starter, and he’s yet to allow more than two earned runs in any of his three starts. Weaver struck out seven in six innings against the Reds on Friday and pitched the first of the Cardinals’ three consecutive quality starts.

The one starter who didn’t get a chance to feast on Cincinnati’s pedestrian lineup was Wainwright. In his one start at Wrigley last season, Wainwright went 7 2/3 innings and allowed two runs – building on what’s been a career of success at the Friendly Confines. Wainwright is 10-2 with a 3.79 ERA in 23 games (18 starts) at the Cubs’ home. He’s coming off an assertive, seven-inning start against Milwaukee that was a catalyst for the strongest stretch thus far by the rotation. They have five quality starts in their past six games, and as a group they have a 2.37 ERA in the past week.

The Cubs, at 7-7, are still waiting for that run from their starters. Only Kyle Hendricks, whose start against the Cardinals was bumped by Monday’s postponement, has an ERA lower than 4.40. Hendricks is one of two Cubs starters to average more than five innings an appearance. The other, Tyler Chatwood, who was one of two free-agent starters the Cubs signed this offseason, has yet to win a game. After a chilly, sloppy game Saturday, the Cubs postponed their game Sunday against the Braves. Chatwood was set to start that game, then announced as Monday’s starter, and now will draw Tuesday.

The Cubs also plan to activate first baseman Anthony Rizzo from the disabled list, though the team will tread carefully with his sore back and frigid temps.

On Wednesday, they’ll stick with Jon Lester as starter.

The lefty has personified the Cubs’ turnaround — his arrival heralded their return to the postseason, and his success against the Cardinals has coincided with the Cubs’ run of division titles. In 2015, Lester’s first season with the Cubs, he started three times at Wrigley against their rivals. The Cubs didn’t win one of them, didn’t score in two of them. The Cubs haven’t lost one of his four starts at Wrigley against the Cardinals since.

In the clubhouse Sunday after the rain cleared and the sweep happened with the first one-run win of the season, Matheny called it “one of those tough games where we’ve got to do those little things right.” Then they packed their bags and headed to Chicago, where one of the big things they couldn’t get right last season awaits. The Cardinals’ push to return to the postseason has many stops, many months to go, but one roadblock hasn’t changed.

They have to go through Wrigley.

Weather permitting.

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