Every year at the start of free agency, a few wiseacres tweet bogus information about NFL free agent signings, purportedly from real NFL insiders. Today ESPN fell for a fake tweet on live television.

It started this afternoon when a Twitter impostor pretending to be Jay Glazer of FOX Sports reported that free agent defensive end Olivier Vernon would sign with the Jaguars. Someone at ESPN saw the tweet, didn’t realize it was fake, and informed ESPN’s on-air people of the report, which they proceeded to discuss on NFL Live. Trey Wingo, Adam Schefter, Tedy Bruschi, Herman Edwards and Tim Hasselbeck all spent several minutes discussing how Vernon would affect the Jaguars’ defense.

And then Schefter piped up to inform his co-workers — and the audience — that the whole thing was bogus.

“Sometimes people get duped by fake accounts,” Schefter said. “And there are people here who got duped by a fake account. There’s no deal with Jacksonville right now. . . . We apologize for that mistake, and we’ll keep you posted when Olivier Vernon does sign a deal.”

It was a regrettable mistake, but one that could happen to anyone who broadcasts live on the air. It was also a good reminder that on the busiest day of the NFL year, it’s a good idea to double-check sources.