ATLANTA -- The Pirates lost their hottest hitter when Ronny Cedeno was a late scratch from the lineup Friday night against the Braves because of lower back tightness.

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

Bobby Crosby took Cedeno's spot at shortstop and in the eighth spot in the order. Cedeno hit leadoff for the first time this season in the series finale at Cincinnati on Thursday, and he was 2-for-4 with a pair of doubles.

The native of Venezuela missed a couple days during Spring Training because of a sore back. But the only previous times he had missed action during the season were because of the flu in April and after being hit on the pinkie by a pitch in early May.

Cedeno, 27, has played in 44 games and is batting .258 with four homers and 14 RBIs.

Morton placed on DL with shoulder fatigue

ATLANTA -- With Charlie Morton's record having fallen to a Major League-worst 1-9 the night before, the Pirates placed the right-hander on the disabled list Friday because of right shoulder fatigue and promoted Steven Jackson from Triple-A Indianapolis to work out of the bullpen.

Morton lasted just two innings at Cincinnati on Thursday in the Pirates' 8-2 loss, allowing seven runs (five earned) on eight hits, and his ERA jumped to 9.35.

"Charlie has been battling mild shoulder discomfort and fatigue off and on for the majority of the season," General manager Neal Huntington said on Friday in announcing the roster move. "Charlie has not wanted to use it as an excuse and has worked to pitch through it.

"Until now, we felt we could work through the issue without risking additional damage. We now feel that the best way to get Charlie back on track is to give his shoulder appropriate rest and recovery time to allow him to get back to 100 percent."

Pirates manager John Russell revealed after the loss to the Reds that Morton had been having shoulder issues for the past few starts. But the pitcher said that he didn't feel pain while pitching and downplayed any health problems.

Clearly, the Pirates feel that Morton needs to get a fresh start mentally and physically. He will spend time in Florida while on the DL and then go out on a Minor League rehab assignment.

"I think it will be good for him," said Russell, who called Morton's time away a chance to "regroup."

"I think [with] the physical and mental drain of trying to piece it together, it will be good to get away from this atmosphere," Russell said, "to try to relax and get a little bit fresher outlook on things.

"He put a lot of pressure on himself and I think it led to the shoulder fatigue. He's been trying so hard to make things work."

Morton, 26, posted a 14.45 ERA while losing his first four starts, before getting his lone victory against the Cubs in Chicago on May 5. Although he hadn't won since, he had some encouraging outings before taking a big step back against the Reds.

Morton was acquired from the Braves last June as part of the Nate McLouth deal and went 5-9 with a 4.55 ERA in 18 starts for the Pirates. He broke into Majors with the Braves in 2008 and was 4-8 with a 6.15 ERA in 16 games.

With Morton on the DL, the Pirates are expected to call up someone from Indianapolis by Tuesday. That is when Morton's next start was scheduled to fall, with the Pirates playing the Cubs in Chicago.

Jackson, 28, was 1-0 with a 3.42 ERA in 17 relief appearances with the Indians. He was claimed off waivers from the New York Yankees last May, and he was 2-3 with a 3.14 ERA in 40 relief appearances with the Pirates.

Indianapolis was in Charlotte, and Jackson, a South Carolina native, drove to Atlanta on Friday with his wife, Lindsay, and 7-month-old daughter, Molly. They had come down for a Memorial Day weekend visit.

"I didn't start out very well this season, but it had been going real good lately," Jackson said.

LaRoche easing back into game action

ATLANTA -- Andy LaRoche was back on the bench for the series opener against the Braves, but manager Jack Russell said that the third baseman hadn't suffered a setback.

"He's fine," Russell said.

LaRoche returned to the lineup on Thursday in Cincinnati after missing five games because of a sore back. He was 1-for-4 at the plate and made a throwing error in the 8-2 loss to the Reds on Thursday.

"I wanted to see how he made it through, and everything came out pretty well," Russell said. "We're going to careful in not running him out there every day and have it flare up on him again."

Akinori Iwamura returned to the lineup with LaRoche resting and Neil Walker moved back to third base after getting a start at second in place of Iwamura in the series finale against the Reds.

LaRoche played in 36 of the Pirates' first 48 games, hitting .256 with three homers and 10 RBIs.

Prospect Alvarez heating up in the Minors

ATLANTA -- Third baseman Pedro Alvarez, who was 4-for-5 with Triple-A Indianapolis on Thursday night, is starting to hit like the Pirates expected.

The No. 2 overall pick in the 2008 First-Year Player Draft had 10 hits in his past 24 at-bats after the breakout game at Charlotte, with four doubles, a homer and seven RBIs during the eight-game stretch.

Alvarez, 23, was hitting .310 in May compared to .224 in April, and his average was up to .267. The former Vanderbilt standout has 10 homers and 43 RBIs in 47 games. He has walked 22 times compared to 45 strikeouts, posting a .354 on-base percentage to go with a .517 slugging mark.

The left-handed hitter homered on Opening Night for Indianapolis, but then suffered some lean times at the plate. Alvarez's fielding, not considered a strength, has remained more steady. He has made only five errors.

Alvarez spent last season with Lynchburg of the Class A Advanced Carolina League and Altoona of the Double-A Eastern League, hitting a combined .288 with 27 homers and 95 RBIs.

Eight prospects make Minors All-Star Game

ATLANTA -- Bradenton led the selections on Friday for the Florida State League All-Star Game, placing eight players on the South Division roster.

Chosen for the June 12 showcase in Viera, Fla., were pitchers Bryan Morris, Nathan Adcock, Noah Krol and Jeff Locke, catcher Tony Sanchez, infielders Brock Holt and Jeremy Farrell and outfielder Quincy Latimore.

Morris, a former first-round draft choice by the Dodgers, was the leading vote-getter, despite being promoted to Double-A Altoona on May 16. He was 3-0 with a 0.60 ERA in eight starts for the Marauders and is 2-0 with a 1.64 ERA for the Curve.

Bradenton holds first place in the South Division as a first-year Florida State League member. The Pirates moved their Class A Advanced farm team to Pittsburgh's long-time Spring Training base this season from the Carolina League.