CHICAGO -- Adding reinforcements, the Phillies called up four players to help with their September playoff push.

Outfielder Greg Golson and catcher Lou Marson, who also was a member of the Bronze Medal winning U.S. Olympic Team, had their contracts purchased from Double-A Reading. Each will be making his Major League debut when they are needed in a game.

Pitchers Adam Eaton and J.A. Happ were recalled from Triple-A Lehigh Valley to serve in relief roles. To make room for Golson and Marson on the 40-man roster, the team transferred pitchers Tom Gordon and Francisco Rosario to the 60-day disabled list.

On Sept. 1, Major League rosters may expand from 25 players to 40.

"We definitely can use Golson because of his speed and defensive skills," manager Charlie Manuel said. "Marson gives us a third catcher. I [switch] catchers a lot, so I'll use him."

Golson, 22, made major strides at the plate this season with Reading, as he batted.282 with 13 homers, 60 RBIs and 23 stolen bases. The concern remains his high strikeout totals, having fanned 130 times in 426 at-bats. He'll mostly be used as a defensive replacement and pinch-runner.

Marson, 22, hit .314 with five homers and 46 RBIs in 94 games with Reading, and .308 in five games (four starts) in Beijing.

"I've known him since he signed, and I understand he's really coming along," Manuel said. "He's got some experience."

Eaton combined to go 0-5 with a 7.02 ERA in seven starts, while he appeared in three games for Philadelphia, starting two of them. He went 8-7 with a 3.60 ERA and 151 strikeouts in 135 innings for Triple-A Lehigh Valley.

"Eaton, we said we would bring him back on September 1st, so we're bring him back," general manager Pat Gillick said. "Happ is a left-hander who we can match him up against somebody. I don't know if he'll get into crucial games but he'll give us depth that we don't have."