PITTSBURGH -- Cubs pitcher Carlos Zambrano, on the disabled list with low back soreness, struck out four and gave up one unearned run over four innings in a rehab start for Class A Peoria.

Zambrano (6-4, 4.34 ERA) threw 63 pitches, 38 for strikes. He is expected to be activated on July 16 when eligible to come off the DL. He will throw July 14 when the Cubs return from the All-Star break.

The right-hander gave up leadoff singles in the first two innings, but escaped without allowing a run. In the third, Beloit's Tobias Streich walked and moved up on a sacrifice bunt. Wang-Wei Lin was safe on an error by second baseman Arismendy Alcantara, which allowed Streich to score.

In the fourth, Zambrano walked the leadoff hitter but got the next batter to hit into a double play, then struck out Andy Leer.

Zambrano is headed to Guatemala on Sunday to complete paperwork in his adoption process of a 2-year-old boy whom the Cubs pitcher met when he was 5 months old. Zambrano's Big Z Foundation is donating clothing and 100 pairs of shoes to an orphanage as well.

Dempster to take mound on Saturday

PITTSBURGH -- Cubs pitcher Ryan Dempster will get one more start in the first half, as he goes Saturday in the second game of a three-game series against the Pirates.

Dempster (5-6, 4.99 ERA) was scratched from Monday's game against the Nationals because of back problems and discomfort in his core.

"He felt good today and says he's good to go," Cubs manager Mike Quade said Friday.

Quade also said he wouldn't hold Dempster back, even though he hasn't started since June 29.

"If he's physically OK, I don't see why 100 pitches aren't in his grasp," Quade said. "If he does fatigue, he'll let us know."

Cubs release outfielder acquired in Garza trade

PITTSBURGH -- The Cubs released outfielder Fernando Perez, who was acquired from the Rays in the Matt Garza deal.

Perez, 28, was batting .238 with three home runs and 20 RBIs in 73 games with Triple-A Iowa. He led the team with 17 stolen bases in 19 attempts.

"It just became a situation where we did not project him being able to come up and help like we wanted him to do," Cubs general manager Jim Hendry said. "He can run, but the bat didn't come around like we thought and neither did his outfield play."

With Lou Montanez and DJ LeMahieu in Iowa after stints with the big league team, Perez became the odd man out, Hendry said.

Hendry also expected player development director Oneri Fleita to make more roster moves in the second half to promote some players.

"We'll be moving a lot of prospects up a level, all the way from [low Class A] Boise up for the second half," Hendry said.

The Cubs acquired Perez along with Garza and Minor League pitcher Zach Rosscup from the Rays in January in exchange for five players -- Chris Archer, Robinson Chirinos, Brandon Guyer, Hak-Ju Lee and Sam Fuld. With the move, the Cubs' 40-man roster is now at 39.

Barney adjusting well to eight-hole

PITTSBURGH -- Darwin Barney seems to be a good fit in the eighth spot in the Cubs' lineup. He entered Friday's game batting .421 (8-for-19) there, compared to a .290 average when batting second.

"Every spot in the National League order is important," Barney said. "The eighth spot is different than the seventh or sixth hole, because you have the pitcher behind you. The situation of that at-bat dictates what type of hitter you have to be and how patient you need to be and what pitches to look for."

Barney said he was well prepared for the eight-spot. At Double-A Tennessee, he would be either third or eighth in the lineup.

"It's a little different being in the three-hole than the eight-hole," he said.

The Cubs most likely won't have Barney batting third.

"The way I look at it is I'll have more opportunities to hit with men on base, and anybody who plays this game enjoys those opportunities," he said about batting eighth. "As the game goes on, your role changes [because of pinch-hitters in pitcher's spot] and I'm comfortable with that. I'm the kind of hitter who if I'm hitting two, I go up and my plan is dictated by the situation. It's pretty much the same role hitting in the eight-hole."

He seems to be adjusting just fine.

Reliever Mateo has strained right elbow

PITTSBURGH -- Cubs pitcher Marcos Mateo has a strained right forearm that is similar to what Randy Wells had but is not as severe, and he is expected to be sidelined for at least four weeks.

Mateo, who appeared in 23 games in relief with the big league team, will go to Mesa, Ariz., to rehab.

The right-hander had to leave Monday's game because of soreness in his elbow and the Cubs feared the worst.

"When you go off [the mound] like that and your hand is tingling and everything, the first tell-tale sign is usually the elbow," Cubs general manager Jim Hendry said.

The results of the MRI were welcome news, as they showed no damage to Mateo's elbow.