Updated

(SportsNetwork.com) - The St. Louis Cardinals are actively searching the trade market for a starting pitcher. Shelby Miller could change their minds with a strong showing on Saturday, as the Cards continue a three-game set with the Chicago Cubs at Wrigley Field.

Miller has been inconsistent as a starter this season for the Cards and was relegated to bullpen duty after the All-Star break. However, Carlos Martinez has been equally ineffective, leaving the door open for Miller to get another shot before next Thursday's non-waiver trade deadline.

"I think we accomplished what the goal was from the beginning. Let's get him some rest and he got it," St. Louis manager Mike Matheny said. "He���s had a nice little period here to get himself right, strong and feeling good. Now we need to get him out on the mound and watch him get the consistency with the production."

Miller, who hasn't started since July 10, had struggled so far this season, posting a 7-8 record with a 4.25 ERA. Longevity has also been an issue, as he has gone seven innings or more only three times in 19 starts.

Chicago, meanwhile, will counter with a right-hander of its own in Jake Arrieta, who is winless in his last three starts, but is 5-2 on the year with a 2.12 ERA. Arrieta battled the flu his last time out on Sunday and lost to Arizona, as he allowed three runs for the second straight start and gave up four hits in 6 2/3 innings.

"I wasn't able to eat any solid foods and get enough in my stomach to sustain," Arrieta said. "It was just a weird three days. ... Most days I'll take that outing but I would've liked to do a little more to keep a run or two off the board. You've got to fight through it and give the team what you've got that day."

Chicago broke through first in this series on Friday, as Ryan Sweeney went 2- for-4 with a three-run home run and four RBI to help the Cubs eke out a 7-6 win.

Luis Valbuena smacked a two-run shot and crossed the plate three times for the Cubs, who handed the Cardinals their fourth straight loss.

Kevin Siegrist (1-2) gave up the tie-breaking two-run homer to Valbuena in the seventh and was tagged with the loss.

"He was the right guy, he just couldn't get it done," Cardinals manager Mike Matheny said of Siegrist.

Justin Grimm (3-2) struck out two in a scoreless seventh inning to earn the win.

Chicago starter Travis Wood, who hasn't recorded a win since June 15, allowed seven hits and five runs -- two earned -- in five innings of work.

"I really wanted to go deep in the game," Wood said. "I wasn't really throwing pitches all over the place. They fouled off a lot of pitches today and made me work. I was only able to go five, but luckily I was able to keep it close and we were able to pull it out."

These rivals have split 10 meetings this season.