It appears Mike Greenberg has a lot to learn before launching his own “SportsCenter”-like show in the new year.

Several of Greenberg’s ESPN colleagues questioned his news-breaking credibility Thursday after the radio host cited a “general sense” around the NFL that tension was growing between Andrew Luck and the Colts, pushing the quarterback out of Indianapolis. Both Mike Golic Jr., the son of Greenberg’s longtime “Mike & Mike” co-host, and respected NFL insider Adam Schefter disputed the quality of Greenberg’s report.

A day after Greenberg dropped the Luck bombshell, Schefter appeared on Thursday morning’s “Mike & Mike” and cut him off with a tone of incredulity when Greenberg revisited the subject.

“I know you came up with the statements you did, he signed a five-year contract last year. He’s not going anywhere,” Schefter said of the Colts quarterback, whose status this season remains uncertain as he recovers from shoulder surgery. “They can’t deal him and don’t want to deal him. So, to me, they’re with each other for better or worse. And there remains a question as to when he’ll be back.”

Luck’s agent, Will Wilson, also denied the rumors Greenberg set into motion on Wednesday as a “non-story.” The 28-year-old Luck has five years left on the six-year, $140 million contract he signed before last season.

“The speculation/rumor is simply not true,” Wilson told IndyStar. “Andrew would not have signed a five-year extension last year if he was not committed to the Colts. Complete non-story.”

Golic Jr. took the shaming further on his radio show Thursday morning, which is notable after Golic Sr. and Greenberg’s relationship (although both have denied those rumors) is said to be strained as the two prepare to break up in November. The younger Golic launched into a monologue about who should and should not deliver news on the network before mocking his father’s 18-year partner with an NFL rumors segment.

“Yesterday, something strange happened,” Golic Jr. said on ESPN Radio’s “First and Last.” “We kind of understand generally at ESPN the roles everyone plays here, we’ve got analysts, we’ve got hosts, we’ve got news-breakers. … Generally, Mike Greenberg’s regarded as one of the best hosts we’ve got around this network, a great ability to drive a show, lead discussions, do all these things. But not necessarily break news in the way that he attempted to yesterday. And do it, really, with very little basis of fact underneath it.”

Golic Jr. — who is expected to fill in as Golic’s co-host once Greenberg departs for his new show in New York City and Trey Wingo takes over full-time — went on to play the clip of Greenberg’s Luck report on his show and critique it, sarcastically adding he would “love to see the source on this.”

Then the 27-year-old Golic Jr. asked listeners to call in with rumors of their own to make the point that if Greenberg can spread an NFL report without credible sources, so can the average Joe off the street.

“If you’ve got any NFL rumors, listen, if you’ve heard something, if you live in Cincinnati and you’ve heard something from a guy at the deli about Marvin Lewis’ job, all sources are good sources in this scenario,” he said. “If you’ve got an NFL rumor you believe is worth us getting started here at ‘First and Last’ to try and make waves, ’cause it made waves for Greeny, and we’re not above self-promotion here at ‘First and Last.'”

Greenberg tried to clarify his comments later in Wednesday’s show, but the damage had already been done.

“I want to make it clear, I’m not reporting (Luck) wants out of there or anything like that,” he said. “That’s just a commonly heard rumor, that he doesn’t want to go back on the field because he feels that he played hurt last year and will not want to go back out until he’s 100 percent. That’s not even a rumor, just what people are saying around the situation.”