St. Louis Cardinals outfielder Randal Grichuk watches as his ball...

St. Louis Cardinals outfielder Randal Grichuk watches as his ball leaves the field for a home run against the Chicago Cubs in the second inning of their MLB game at Wrigley Field in Chicago, Illinois. July 21, 2017. Credit: EPA / TANNEN MAURY

CHICAGO — The sliding St. Louis Cardinals made a flurry of moves before the start of a key series against the Chicago Cubs, activating outfielder Randal Grichuk and reliever Zach Duke from the disabled list on Friday and recalling catching prospect Carson Kelly from Triple-A Memphis.

St. Louis also acquired minor league outfielder Tyler O’Neill in a trade with Seattle for left-hander Marco Gonzales, and designated catcher Eric Fryer for assignment. Right-hander Sam Tuivailala and outfielder Magneuris Sierra were optioned to the minors after Thursday’s 3-2 loss to the New York Mets.

The Cardinals began Friday in fourth place in the NL Central, nine games back of division-leading Milwaukee. They were a middling 3-4 since the All-Star break, calling into question the direction of the franchise after its run of five straight playoff appearances ended last year.

The non-waiver trade deadline is July 31.

“I have heard from players that we need a bat. I’ve heard from players that we need bullpen help. Playing better should be what drives us,” president of baseball operations John Mozeliak said. “Watching a game like yesterday, it’s tough to justify going out and playing solely for this year. Think about our season, and some days we hit and don’t hit. Some days we pitch and don’t hit. Then when we do both, we see something like yesterday.

“So maybe the broader question is sort of attitude and culture, something that we either look at to change or shake up. That’s not necessarily something that you can just do at July 31st. It might be something we have to look hard at in the offseason.”

Kelly, who turned 23 on July 14, is regarded as one of St. Louis’ top prospects. He hit .283 with 10 homers and 41 RBIs in 68 games with Memphis.

He was thrust into action against the Cubs when All-Star catcher Yadier Molina was scratched with right ankle discomfort. The Cardinals said Molina was available off the bench.

Grichuk was sidelined by a lower back injury. He started the series opener against Chicago and homered in his first plate appearance, hitting a drive to left in the second inning for a solo shot off Jake Arrieta.

Grichuk made a rehab appearance with Double-A Springfield on Wednesday and went 1 for 4 with a three-run homer.

The 34-year-old Duke is coming back from Tommy John surgery last October. He went 2-1 with a 2.36 ERA in 81 games last season for St. Louis and the Chicago White Sox.

“It’s really a surprise to all of us in the sense that he would be able to contribute this month,” Mozeliak said. “I really thought if we saw him sometime in August, that would be great.”

O’Neill, a third-round pick in the 2013 draft, hit .244 with 19 homers and 56 RBIs in 93 games with Triple-A Tacoma. He will report to Memphis.

“This is a player that has a lot of offensive upside,” Mozeliak said. “At 22, he has accomplished a lot already at Triple A. So, for us, it just adds to our offensive depth.”

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