Dempster missed his Monday start because of back soreness and stomach problems. He was hospitalized overnight for observation on Saturday. But on Thursday at Nationals Park, he was able to do a normal side session in the bullpen and then went for a run with pitcher Chris Carpenter.
"As long as I feel good [Friday], I don't see any reason why I can't pitch on Saturday," Dempster said.
Cubs manager Mike Quade didn't want to commit to Dempster until he sees how the right-hander feels on Friday.
"He hasn't exerted himself like that with a side since all this went down and since his last start," Quade said.
Dempster joked that his side session was "epic," and possibly the best he's thrown all year. But he was a little nervous when he was in the hospital.
"When you're laying there in a hospital room and don't have the answers, you wonder," Dempster said. "They took good care of me and hopefully everything is all right."
The Cubs, who have put 13 players on the disabled list in the first half and used 10 starting pitchers, can use some good news, and having Dempster return would qualify.
"If you sit there and sulk, nobody on the other side of the field feels sorry for you," Dempster said. "Why feel sorry for yourself? We've lost before, whether it's as individuals or as a team. We've lost games whether it's here or somewhere else. The easiest way to get through that is to stay upbeat and focus on today's game.
"We can file all the appeals we want to the league, but we can't get those games back. The easiest way is to focus on winning today's game and not where we'll be at the All-Star break, just today."