© 2013 MLB Advanced Media, L.P. All rights reserved.

6/20/2013 6:28 P.M. ET

Long game highlights bullpen's recent success

CINCINNATI -- The Reds' 2-1 win over the Pirates in 13 innings on Wednesday was another strong night for the team's bullpen, as five relievers combined to work six scoreless innings.

Entering Thursday, Cincinnati's bullpen has a 0.47 ERA in its last six games, with one earned run allowed over 19 1/3 innings. Following a period of struggles, the team has a 0.90 ERA -- three earned runs over 30 innings -- in the previous nine games.

"It goes in cycles," Reds manager Dusty Baker said. "You're glad you've got the matchups that work. Sometimes, you match them up and it's not working. Or you've got matchups you're hoping that work and it doesn't work."

On Wednesday, lefty Manny Parra earned his first victory of the season after he pitched the 13th inning and allowed only a two-out infield hit.

Parra, who has a 6.00 ERA in 17 appearances, has not allowed a run in any of his last five outings. He has been developing his breaking ball with the aid of fellow lefty reliever Sean Marshall.

"He's got the stuff. I've told him that there a lot of left-handers having success that don't have the stuff he has," Baker said. "They don't throw 91-94 [mph]. It's a matter of location and when you throw stuff. There were a couple of games that I had to match him up out of need that he shouldn't have been in there. That happens, too, if your bullpen is overworked."

The bullpen stumbled in Thursday's 5-3 loss, as Alfredo Simon was charged with the loss after loading the bases in the seventh. He was replaced by Tony Cingrani, who allowed a bases-clearing double to Pedro Alvarez. J.J. Hoover allowed one hit in two innings of relief with three strikeouts.

Heisey likely to return to Reds by Tuesday

CINCINNATI -- Barring another setback, it appears outfielder Chris Heisey will be back with the Reds by Tuesday, when the club begins a two-game series in Oakland.

Heisey, who has been on the disabled list with a strained right hamstring since April 29, was 2-for-3 with a walk on Wednesday during his second rehab game for Triple-A Louisville.

"I'm hoping he will be ready for Oakland, that's what I'm planning on," said Reds manager Dusty Baker. "That's how I mapped out his schedule to play."

Heisey is 4-for-7 with a double in two games with Louisville. Baker very much wants his right-handed bat at his disposal once again. The Reds will use the designated hitter next week when they play the A's and Rangers at their American League ballparks.

"I need a little more pop," Baker said. "You see I'm sending up left-handers against left-handers here. Sometimes it works, but that's not the way it's intended. We were left-handed short last year and right-handed short this year."

Marshall's shoulder rehab progressing nicely

CINCINNATI -- Injured Reds left-handed reliever Sean Marshall has continued to make progress in his efforts to return from the disabled list. Marshall, who went on the DL for a second time on May 24 because of shoulder tendinitis, long tossed from 120 feet on Wednesday and 135 feet on Thursday.

"I'll be pitching from flat ground by the end of the week," Marshall said before throwing Thursday. "Then we're on my way to the mound."

After being shown video by Reds coaches, Marshall realized his mechanics were causing some of his pain, and he has worked to improve his delivery.

"I'm just building arm strength. It's coming along well," Marshall said.

Sometime around the All-Star break would seem like a realistic return schedule for Marshall, but there is no known target date.

"I wish I had a date to shoot for," Marshall said. "It's flat-ground work to bullpen work to simulated games and then [Minor League] game work, and then I'm in."

Worth noting

• There was a scoring change made in Wednesday's game -- a 2-1 Reds victory over the Pirates in 13 innings. In the third inning, Russell Martin reached base and Starling Marte scored on what originally was ruled an error against Bronson Arroyo when the ball went off of his glove. It has been changed to a single and an RBI. Arroyo was charged with an added hit and his one run allowed in the game was earned.

Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.