Kotsay, who has been on the 15-day disabled list since May 30 with a lower back strain, said he is optimistic that he'll be able to play again in about a week.
"There's nothing definite with this whole procedure and plan," Kotsay said.
"He's coming along pretty good," Braves manager Bobby Cox said.
When told that Kotsay hoped to be back in about a week, Cox said, "He might. Those backs."
Kotsay hit soft tosses in the Braves' indoor batting cage before Friday night's game against the Mariners. It was the first time he swung a bat since experiencing discomfort before the Braves' game on May 26.
"I felt good," Kotsay said. "I didn't hold anything back."
Kotsay said Friday was "kind of a big day" and that he's anxious to see how his oft-injured back will respond on Saturday morning. He also planned on shagging balls and undergoing more rounds of physical therapy at some point on Friday.
If his back responds well, Kotsay said that he would likely hit soft toss again on Saturday and increase his other activity accordingly.
"Being away, out of it for this long, makes it frustrating," said Kotsay, who is batting .294 with four homers and 21 RBIs this season.
When Kotsay's back tightened up before the Braves' May 26 game, he decided it would be best to rest rather than risk further injury. When the pain did not dissipate in the following days, the Braves had no choice but to put the center fielder on the DL.
Kotsay had back surgery during Spring Training in 2007 and played in a career-low 56 games last season. He has played in 47 of the Braves' 74 games this season.
In other injury news, Rafael Soriano's pitching status remains day-to-day.
"He still doesn't feel real good," Cox said of Soriano. "When he throws about 90 percent, he can feel it."
Cox said the reliever has played catch, but no bullpen session has been scheduled. Soriano was placed on the DL on June 11, retroactive to June 6, with right elbow inflammation.
Soriano is eligible to come off the DL on Saturday, but it appears unlikely that he will be activated.
Ryan Lavner is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.