Dunn, who had an appendectomy in the early hours of Wednesday morning, was not in the starting lineup. Carlos Quentin was moved to the designated hitter spot and Brent Lillibridge was inserted into right field.
"I'm really disappointed that I'm not playing in this game today," Dunn said. "I know it probably doesn't mean a lot, just another game to a lot of people, but home openers are really special especially when it's your first one [with a new team]. I definitely wanted to be out there and it's not going to work."
Dunn looked to be in pain merely sitting down in the chair in front of his locker. Rating himself with an above-average pain tolerance, Dunn said it wasn't so much the discomfort that was the issue, but rather the lack of mobility in his lower abdomen.
"It's not the pain," Dunn said. "I feel like when I swing, my belly button is going to go shooting at the pitcher. That's a bad visual. Seriously. That's what it feels like.
"My main goal was to get out there today. That's not going to happen, so I want to get it to the point where it's not bothering me."
His original timetable to return was an optimistic five days, but Dunn still has designs on beating that.
"The timetable is tomorrow now. I just had to push it back a day," Dunn said. "Hopefully [Friday] it will be better. That's what I'm shooting for."
That just sounds like Dunn's optimism speaking, or maybe the pain medication.
"I think that was the problem [Wednesday]," he said. "I think I was on too good of [painkillers] [Wednesday] while I was talking, so ... I tried everything last night and today to do it and it ain't happening."
Manager Ozzie Guillen said he made Thursday's lineup without even consulting Dunn.
"I appreciate when the guys want to play for you but in the meanwhile, we have to be careful when you have surgery, no matter how small it is, it's still dangerous," Guillen said. "We have the people who can replace him for a couple of days. Hopefully when he comes back, he'll be fine."
When the abdomen discomfort first surfaced Sunday, Dunn said he knew it wasn't a muscle issue. It bothered him the most when he was lying in bed. Knowing that the Cardinals' Matt Holliday had his appendix removed on April 1, Dunn said he looked up the symptoms on the Internet and told doctors of his findings.
Dunn was asked why appendix issues are so popular in baseball right now.
"I don't know if it's the weather or it could be the radiation from Japan or something ... I don't know," Dunn said. "Something is not right."'
Doug Padilla covers the White Sox for ESPNChicago.com and ESPN 1000.