Could UFC heavyweight star Alistair Overeem be out of his blockbuster showdown with Brock Lesnar at UFC 141 on December 30th?

That was the big rumors sweeping through press row following this evening’s UFC 140 event in Canada, with Yahoo! Sports Kevin Iole the first to mention it on his Twitter account.

Such was the buzz about it that MMAfighting’s Ariel Helwani queried Dana White about it during the post-fight press conference, but the UFC president denied it, stating that if a fighter had pulled out then he would have heard about it before the media.

Nevertheless, they say there’s no smoke without fire and rumors persist that the Dutch striker’s debut in the UFC may be in jeopardy.

Right now the suggestion is that there may be some connection to a pre-fight drugs test, with ESPN’s Josh Gross noting on Twitter that Overeem’s name is listed on the agenda for the Nevada State Athletic Commsion at a meeting on Monday.

Overeem has been plagued by rumors of steroid abuse in recent years after bulking up from light-heavyweight to a heavily muscled 260lb heavyweight fighter while fighting mainly in Japan, but it should be stressed that he’s never failed a drugs test.

The only thing we do know for sure at this stage though is that Overeem did abandon his U.S training camp at Xtreme Couture after just a few weeks recently to return to Holland, but he had explained this was in order to tend to his mother who had taken ill and that the fight was still on.

Incidentally, if he did by any chance happen to be out then they may well have a ready-made replacement on hand to fill in for him.

After hearing the discussion at the presser about Overeem’s potential absence, Frank Mir, who produced a spectacular kimura finish against Big Nog this evening, decided to offer his services saying that he’d take the fight against his old nemesis Lesnar on three weeks notice.

A third fight between Lesnar and Mir is something that fans have been indifferent to up to this point, but on such short notice it would be as good a replacement as they could hope to find.

People really want to see Overeem Vs Lesnar though, so let’s hope that the rumors aren’t true and that the original main event is still very much intact.

If it’s not then given the tight timescale we should be hearing about it sometime next week so stay tuned for the latest updates.