ATLANTA -- Whether it's at third base or second, Neil Walker has become an everyday regular in the Pittsburgh lineup.

"I guess I'm a little bit surprised, but at the same time this is what I was preparing myself for," Walker said. "I'm not here just to be here. I want to contribute."

The switch-hitting rookie started his fifth consecutive game since being promoted from Triple-A Indianapolis on Tuesday. Three were at third base and he was in the lineup at second base for the second time Saturday night against the Braves.

Runs haven't been coming easily for Pittsburgh and Walker had two doubles in Friday's 7-3 loss to Atlanta as he raised his average to .294. He was hitting .321 in Triple-A and his success there has carried over.

"I think I've been able to find the confidence to really believe in myself up here," the 24-year-old said. "I'm a lot more comfortable at the plate, as well as in the field. And also being able to play second base and the outfield now gives me more opportunities."

The Pittsburgh native was up briefly with the Pirates last season, but hit just .194 in 17 games.

"He was a little awestruck," manager John Russell said. "It was so new to him. Now he knows what to expect. And having very good success down there [at Indianapolis] built some confidence. ... He's got over that hump [where he knows] 'I did it down there and now I know I can do it up here.'

"Obviously, you've got to give him credit. He's played well. We're struggling scoring runs and he's hit the ball. I'm not a rocket scientist. But I can figure out when a guy is swinging the bat pretty well, you want him in the lineup."

Jakubauskas throws bullpen session

ATLANTA -- Chris Jakubauskas, who suffered a concussion when struck in the head by a line drive April 24, returned to the mound for the first time Saturday and threw 30 pitches during a bullpen side session.

"It felt good," the right-hander said. "Step one over, now we'll move on to step two. I'll throw another side in a couple days. It didn't feel like a month [since I'd been on the mound], so I'll take that as a positive."

Jakubauskas was hit on the right side of the head near the back by a liner off the bat of Lance Berkman in the first inning of a start at Houston and suffered a laceration as well as the concussion.

Jakubauskas, 31, was claimed off waivers from Seattle during the winter. He was 6-7 with a 5.32 ERA for the Mariners last season, making eight starts and 27 relief appearances.

Prospect Lincoln ruled out for Tuesday

ATLANTA -- Pirates manager John Russell ruled out top Pirates pitching prospect Brad Lincoln as a possibility to start on Tuesday night against the Cubs in Pittsburgh. The Pirates need someone to take the place of Charlie Morton, who went on the disabled list Friday.

"He doesn't line up," the manager said. "I don't see that as a possibility."

Lincoln would be working on just four days' rest if he started Tuesday. But he needed only 61 pitches while working five scoreless innings for Indianapolis in a suspended game Friday night at Charlotte.

Lincoln, who turned 25 on Tuesday, is 5-2 with a 3.47 ERA in 10 starts, striking out 49 and walking 13 in 62 1/3 innings. Triple-A opponents are batting .218 against him.

The right-hander was the fourth overall pick in the 2006 First-Year Player Draft after being named College Player of the Year as a junior at the University of Houston.

Cedeno back in lineup Saturday

ATLANTA -- Shortstop Ronny Cedeno returned to the Pirates lineup Saturday against the Braves after being a late scratch in the series opener because of a tight lower back. He said he felt discomfort after the game at Cincinnati on Thursday and couldn't get his back loose Friday.

Cedeno, who has been one of the Pirates' hottest hitters, missed a couple days during Spring Training because of soreness in the same area.

"I have to exercise to get my lower back stronger," said Cedeno, who didn't remember doing anything to cause the flare-up.

Cedeno was 7-for-14 with a homer and three RBIs in the four games at Cincinnati and had reached base in 18 consecutive games, getting hits in 10 of the last 11. He was hitting .308 in May going into Saturday after posting a .208 average in April.