Cutler left Sunday's NFC Championship Game against the Green Bay Packers in the third quarter with an injured left knee.
"I don't know if anybody can play the game when they're not 100 percent or not well," Ditka said on "Mike & Mike In The Morning" on ESPN Radio. "I can't speak for Jay Cutler. I can't speak for anybody.
"Myself, I would have had to have been paralyzed to come out of the game. I don't want to say that word. I would have had to be completely knocked out to come out of that football game."
Cutler underwent an MRI on Monday that revealed a sprain to the medial collateral ligament in his left knee. Earlier Monday, it was reported by the Sun-Times that he had torn the MCL.
Before finding out about the injury, Urlacher wasn't questioning his quarterback.
"Jay was hurt," the linebacker said. "I don't question his toughness. He's tough as hell. He's one of the toughest guys on our football team. He doesn't bitch. He doesn't complain when he gets hit. He goes out there and plays his ass off every Sunday. He practices every single day. So, no, we don't question his toughness."
Cutler tried to test the knee by riding a stationary bike on the sideline, where he remained throughout the game.
Shortly after the game, fans began calling sports talk shows to question Cutler's toughness. Urlacher was told that some players around the league were doing the same via Twitter.
Arizona's Darnell Dockett posted on his Twitter account: "If I'm on chicago team jay cutler has to wait till me and the team shower get dressed and leave before he comes in the locker room! #FACT."
Jaguars running back Maurice Jones-Drew added his thoughts with tweets from his account, saying: "All I'm saying is that he can finish the game on a hurt knee... I played the whole season on one..."
"Nothing like jealous people who are sitting home watching," Urlacher said. "Players around the league you said, right? Yeah, love jealous people when they're watching our game on TV while their season is over."
In a postgame show on Fox, Urlacher again defended his quarterback when told fans were critical.
"Who cares what they think?" he said. "That's my response to them. They are not playing in this game. Jay was hurt, obviously. There's no reason for him to be out there if he can't get it done. He was obviously hurt pretty bad or he would have played.
"For them to question his toughness is stupid to me."
Cutler said he injured his knee on the second-to-last series in the first half and then aggravated it on the next series.
"We gave it a go that first series [in the second half], but I really couldn't plant and throw," he said. "So they kind of pulled me.
"I was going to keep playing. But they made the decision that giving Todd a shot would better suit the team."
When told players were questioning him, Cutler said: "No comment on that."
Packers players were surprised Cutler didn't come back.
"You know if he doesn't come back it had to be serious, not to come back and play in this game," Charles Woodson said.
Bears center Olin Kreutz was not surprised, and he said he could see Cutler's leg shaking during a huddle in the second quarter.
"I didn't even think he was going to finish the half," Kreutz said. "When he came back to try it again, that amazed me. It was shaking right after he took the hit and walked back in the huddle. It was swinging like this [waving his hand back and forth].
"So I knew one of his ligaments probably went. I can't remember exactly what play it was. I know it was the second quarter. I remember him walking in the huddle, and I saw it shaking like this. I said, 'Ah, man.'"
Kreutz also shot back at Cutler's critics on Twitter.
"I don't know what somebody might have said, but that's just ignorance," Kreutz said. "They should turn that [expletive] Twitter off."
Bears coach Lovie Smith said Cutler was disappointed.
"He was hurt, and he couldn't go," Smith said. "Trainers, doctors and all, they are the ones who really made that decision. As far as Jay he is like everyone else; he was disappointed he couldn't go out and play to help his team win."
Smith wasn't happy when asked again about Cutler not returning.
"He hurt his knee and he was out, all right? There's nothing else for me to tell you on that," Smith said. "I don't know exactly when it happened. He couldn't go, and we moved on. Let's go to some other questions, how about that?"
Bears receiver Rashied Davis also supported Cutler.
"You know yourself better than anybody, and Jay is a very tough guy. You've seen it," Davis said. "For him to go out of a game, something had to be wrong. I don't know what it is, but Jay is a pretty tough dude."
Ditka said that some of the criticism seemed too much and that Cutler must have been hurt pretty bad to miss such a big game.
"I don't know. I feel it's very unfortunate when the whole country comes out and says ... I get texts from people, I couldn't believe them. I said, 'You people are demented,' Ditka said on ESPN Radio.
"I don't think you can take yourself out of a game unless you're really hurt. A game of that significance for the Chicago Bears playing the Green Bay Packers for the chance of playing for the Lombardi Trophy. To me, that's pretty significant."
Cutler has been a lightning rod of controversy since coming over to the Bears in a trade with the Denver Broncos before the 2009 season. Cutler's first year with the Bears was disastrous as he threw 26 interceptions and Chicago finished 7-9.
But Cutler improved this season, despite an offensive line that yielded the most sacks in the NFL. And despite the constant battering he took, Cutler missed only one game after suffering a concussion.
Cutler wasn't effective Sunday as he completed 6 of 13 passes for 80 yards and an interception in the first half. He tried to play in the third quarter, but after a three-and-out series, he left and would not return. He finished with a passer rating of 31.8.
ESPNChicago.com Bears reporter Michael C. Wright contributed to this report. Information from The Associated Press was used in this report.