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4/10/2014 7:51 P.M. ET

Renteria abandons righty-lefty platoon vs. Cole

CHICAGO -- Cubs manager Rick Renteria abandoned his righty-lefty platoon and started right-handed hitters Mike Olt and Junior Lake against Pirates righty Gerrit Cole on Thursday.

Part of the reason is the splits against Cole are identical. Left-handed and right-handed hitters have both hit .251 against Cole through his career entering Thursday.

"These are two young players who we're going to try to get them as much playing time as we can," Renteria said of Olt and Lake. "We're trying to find spots that can give them an opportunity to gain some confidence.

"Everybody on the squad, everybody, from [Darwin] Barney to [Ryan] Sweeney to [Nate] Schierholtz, every one of those guys has been working real hard and they all want to be in the lineup," Renteria said. "We're just trying to balance it all out and give us the best chance on a daily basis."

Sweeney and Schierholtz have started against right-handed pitchers this year, but they are batting .118 and .174 respectively, heading into Thursday's game, which Schierholtz started, batting fourth. Lake entered the game hitting .273, while Olt had two home runs and was batting .158.

The Cubs have scored 21 runs in their last three games after scoring eight runs in the first five games. What gives?

"Their approaches are solid, and they're getting good pitches to hit," Renteria said. "They're feeling a little confident now, which is good."

Rondon riding 15-inning scoreless streak

CHICAGO -- It took some extra work in Venezuela for Cubs reliever Hector Rondon to find his breaking pitches.

Rondon extended his scoreless streak to 15 innings when he pitched the ninth in Thursday's 5-4 loss to the Pirates. The stretch dates to Sept. 3 of last season. It ranked among the top three longest such streaks in the Major Leagues.

"My mentality is way different," Rondon said Thursday. "I think I trust myself and my command of my pitches. That's the difference right now."

Last September, Rondon, a Rule 5 Draft pick, did not give up a run -- and only served up one hit -- over nine innings in nine relief outings.

"I put in my mind last year, the last month of the season, when it was over, I told the manager [Dale Sveum] that I was going to play winter ball in Venezuela, and I worked on my breaking ball," Rondon said. "I went there and worked on that and came into Spring Training, and I feel really good about how I throw my breaking balls. I did the same thing that I did last September. I think that helped me a lot."

In four games so far, Rondon has given up three hits, walked two and struck out eight over six innings.

"Everything is really good right now," he said.

Cubs Charities to help improve local fields

CHICAGO -- Cubs Charities, in partnership with Local Initiatives Support Corporation Chicago, announced the launch of the "Diamond Project," which aims to improve the quality and safety of local baseball fields in the Chicago area.

The project will expand opportunities for children to play baseball, create or preserve green space and foster a love of the game, particularly in the inner city.

The "Diamond Project" is the third signature program Cubs Charities has launched, following the Cubs Scholars program and the "Cubs On The Move" fitness trolley.

Cubs Charities, with technical assistance from LISC Chicago, will identify communities in need of new or improved baseball fields and provide grants to facilities that will be used to promote health and wellness through baseball. In addition to monetary support, the Wrigley Field grounds crew will advise Diamond Project grantees during projects and maintenance.

For nonprofit, neighborhood-based organizations and schools in the Chicago area, an informational session will be held at Wrigley Field on April 30 at 10 a.m. CT in the Budweiser Bleacher Suite. Anyone interested in attending should send an email to diamondproject@cubs.com. For additional information, visit cubs.com/diamondproject.

Extra bases

• Cubs pitcher Jake Arrieta struck out four and gave up three hits over 3 2/3 scoreless innings in his second rehab start for Double-A Tennessee on Thursday. He threw 66 pitches, 40 for strikes, against Chattanooga.

Arrieta was slowed this spring because of tightness in his right shoulder. There is no timetable for Arrieta's return.

James McDonald (shoulder) and Kyuji Fujikawa (elbow) are both continuing their rehab at the Cubs' Mesa, Ariz., complex.

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.