Shannon Sharpe made his return to the "Undisputed" set after missing Tuesday's episode over co-host Skip Bayless' controversial tweet about Damar Hamlin's medical emergency ... and it only took a whopping 40 seconds before an argument broke out.
Shannon kickstarted Wednesday's show by addressing Hamlin's situation in his opening monologue ... saying, "Watching that game on Monday night, what happened to Damar Hamlin struck me a little different."
Sharpe explained he's witnessed his NFL brothers suffer serious injuries throughout his career ... but added that seeing someone have to be revived on the field was a completely different experience.
Shannon then addressed Bayless' tweet head-on ... which, according to Skip, wasn't supposed to happen.
"Skip tweeted something and although I disagree with the tweet -- and hopefully, Skip will take it down."
Bayless immediately interrupted his co-host ... saying, "Time out -- I'm not going to take it down because I stand by what I tweeted."
Sharpe was clearly pissed with Skip interjecting ... replying, "I cannot even get through a monologue without you interrupting."
The Hall of Famer then explained his reason for missing Tuesday's show ... saying the discussion should be about Hamlin, not Skip's tweet.
"I didn't want yesterday to get into a situation where Damar Hamlin was the issue. We should have been talking about him, and not get into your tweet. That's what I was gonna do. But you can't even let me finish my opening monologue without you interrupting."
Skip says he was under the impression his tweet was not going to be discussed on the show ... claiming producers did not have an issue with what he said.
As TMZ Sports reported Tuesday, Sharpe's absence was a direct response to Skip's tweet ... which Bayless clarified was not intended to undermine Hamlin's serious medical scare.