CHICAGO (AP) -- Mark Prior knows how to build up his arm strength after a stint on the disabled list. He's had plenty of experience.
In just his fourth start since coming off the DL after a line drive fractured a bone in his pitching elbow, Prior looked strong and ready Thursday, pretty much in top form.
"He's pretty close, way close," manager Dusty Baker said. "It's great to see him throw so many pitches and so many strikes and go eight innings."
If the Cubs have any chance in the second half they need a healthy Prior, who's made five career trips to the disabled list, including two this season.
Prior said his endurance level is pretty much back to where he wants it.
"I'm almost there. Today was a little different because I was on the bases and I haven't been on the bases in a while," said Prior, who helped himself with two singles, a run scored and an RBI.
"I wanted to get my pitch count up. The last couple of games coming back off the DL, it's been 70 to 80 pitches and it's been 100 and I wanted to get it a little more. So when I do need it come August and September, I can go and get it," he said.
"It's been pretty frustrating because I've noticed it's become a trend lately that the bottom of the order's been hitting me," Redman said. "I don't know if I'm easing up or not."
After walking Lawton to start the game, Prior didn't ease up one bit. He found his rhythm, striking out the side in the first.
"With the wind blowing in today he [Prior] was like, 'Go ahead hit it, give it your best shot,'" Lawton said. "He threw every ball where he wanted to. He was pitching with a purpose and that's why he's as good as he is."
With a 15 mph wind blowing in from left field and playing tricks with fly balls, Walker hit a two-run homer to right in the third -- scoring Prior, who had singled -- for a 2-1 Cubs lead.
"I told Lawton before the game that there was no way anybody was going to hit a home run today and I go out and do it and he was all over me the rest of the day for that," said Walker, whose fourth homer of the season just cleared the fence.
After Jeromy Burnitz singled in the fourth, Pirates left fielder Craig Wilson couldn't catch Neifi Perez's fly to the wall that fell for a double. Blanco followed with a two-run double into the left field corner for a 4-1 lead before Prior hit an RBI single.
"A guy that was .063 [Blanco] against lefties had two doubles, and the pitcher had a couple hits and an RBI," Pirates manager Lloyd McClendon said. "You have to get out the eight and nine hitters."
Two Cubs errors helped the Pirates take a 1-0 lead in the third. Jack Wilson reached on third baseman Aramis Ramirez's error and raced to third when Chicago left fielder Matt Murton fumbled Lawton's single.
Lawton took second on the play before Rob Mackowiak ended an 11-pitch at-bat with an RBI grounder to second.
The opener of the four-game series was the makeup of an April 22 game postponed by rain. ... Cubs rookie Adam Greenberg, who was hit in the head by the first major-league pitch he faced from Florida's Valerio de los Santos on Saturday, said he is still a little off-balance and dizzy. Greenberg has a mild concussion and doesn't know when he'll be able to play again. ... Pirates center fielder Jason Bay, who was an All-Star selection, was feeling a little ill Thursday but was in the starting lineup. He was 0-for-4 and is in a 1-for-22 skid. ... The Cubs have won 14 of the last 16 games with Pittsburgh. ... The Pirates have scored two runs or fewer in nine of Redman's 19 starts.