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7/19/2014 6:25 P.M. ET

Renteria voices support for embattled Jackson

PHOENIX -- High expectations have been placed on Edwin Jackson since he signed a four-year, $52 million contract with the Cubs in December 2012. On Friday, Jackson opened the second half with 5 1/3 innings against the Diamondbacks, and did not get a decision. After the game, Renteria complimented Jackson.

"I know he's the guy we seem to pick on, and I thought he did a great job today," Renteria said.

Jackson gets "picked on" because in his first year with the Cubs in 2013, he led the National League in losses, which is not what fans expected when the right-hander signed the hefty deal.

On Saturday, Renteria said his comment might have been a poor choice of words on his part, and then he explained.

"He's a young man who has obviously got here and was expected to do a lot, and rightfully so, and I think he knows it, too," Renteria said Saturday. "I think he's shown he's better than he has been and he continues to progress."

Renteria admitted he's very protective of his players, which prompted the comment. Jackson did not give up the lead against the Diamondbacks in the Cubs' 5-4 loss.

"I know he's had more outings than not where maybe we've taken the lead and he's given it up," Renteria said. "[Friday], he had five-plus very good innings. We had a fresh bullpen and it was a good situation to see if we could leave him in a positive state and something to build on. Even seasoned veterans need things to build on."

Renteria said he feels Jackson has done better this season, but adds, "it's not near what everybody wants, and he would be the first one to tell you, 'I know I can be better.'"

Wada, Straily give Cubs options for fifth starter

PHOENIX -- Cubs manager Rick Renteria was not ready to name a fifth starter on Saturday, but one pitcher in the mix is left-hander Tsuyoshi Wada, who struck out 10 for the third time this season at Triple-A Iowa on Friday.

Wada, 33, leads the Pacific Coast League with 120 strikeouts and ranks second with 113 2/3 innings pitched. The lefty is fourth in ERA (2.77) and fifth with a 1.16 WHIP. He picked up his 10th win Friday and joins Kyle Hendricks with double-digit wins this year. Hendricks already has been named the Cubs' fourth starter, and will be in the rotation on Tuesday. The Cubs need a fifth starter for Wednesday against the Padres.

This year is the first time the Iowa Cubs have had multiple 10-game winners since 2010 when Jeff Samardzija and Jay Jackson each won 11, and Casey Coleman won 10.

Another option is right-hander Dan Straily, who was acquired from the Athletics in the trade that sent Samardzija and Jason Hammel to Oakland. Straily is 0-1 in two starts at Iowa, giving up four earned runs over nine innings. At Triple-A Sacramento this year, he was 4-3 with a 4.71 ERA in 10 starts.

"Straily has been throwing and has been trying to get back on track and we'll see how that develops and somewhere down the road, we'll see if he ends up fitting into that particular spot," Renteria said.

The Cubs need two starters in the second half to fill Samardzija and Hammel's spots in the rotation.

Olt, Lake enduring growing pains at plate

PHOENIX -- Mike Olt and Junior Lake had first halves to forget. Olt does lead all National League rookies with 12 home runs, but entering Saturday, he was batting .144 while Lake was batting .218. Cubs manager Rick Renteria hasn't given up on either player.

"One of the things I try to talk to them about is not focus on the results -- I want them to focus on the at-bat," Renteria said. "It's one of the toughest gigs that they have as young men in the big leagues; to come off the bench and play every three, four, five, six days, and still try to develop.

"I think the biggest thing we try to do is balance their emotional state," Renteria said. "If I can keep their emotional state in check and feel they're still positive, still grinding and not losing a whole lot of their confidence, then we're succeeding. In the long term, yes, we want them to be able to perform. We're still trying to balance that all out."

Olt started for the fourth time in the Cubs' last nine games on Saturday. Renteria has tried to match the third baseman against left-handed starters, and the team simply hasn't faced many.

"We've scattered at-bats throughout," Renteria said.

Lake batted .284 last season, his first in the big leagues, and does have more home runs this year (nine vs. six), but his average has dropped.

Renteria was asked if either Olt or Lake needed more regular at-bats in the Minor Leagues. The Cubs will have to make a roster move Tuesday when Kyle Hendricks is added to make the start. Arismendy Alcantara was promoted from Triple-A Iowa when Darwin Barney went on paternity leave, and was 9-for-26 in six games.

"I don't want to speculate on any of that," Renteria said of possible roster moves. "The biggest thing for us to know is that [Alcantara] will be here through the weekend, and once we sit down and talk about the possible moves, you guys will know."

Renteria keeping trade speculation on back burner

PHOENIX -- The Cubs jumped the market by making a blockbuster trade on July 4. The non-waiver Trade Deadline is July 31, and manager Rick Renteria was asked if he expected another move.

"That's a great question of which I have no answer to," Renteria said Saturday. "At this point in time, I don't try to speculate."

Renteria spent the All-Star break in Chicago with his wife and daughter, exploring the city. He did not meet with Cubs president of baseball operations Theo Epstein or general manager Jed Hoyer.

"I couldn't take baseball out of my head, but they allowed me my time, so I took advantage of it," Renteria said.

The Cubs have a surplus of infielders, especially with Arismendy Alcantara's solid start in six games. Right now, Renteria is focused on the current 25-man roster.

"Nothing surprises me," Renteria said. "We prepare for everything, but [trades are] not something I'm thinking about."

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.