Buffalo Bills linebacker Shawne Merriman came face to face with police in Vegas this morning ... after a friend alerted hotel security that the NFL star may have harmed himself ... but it turned out to be a case of a simple overreaction.

Law enforcement sources tell us ... officers were dispatched to Merriman's room at the Cosmopolitan Hotel after the friend claimed he had received startling text messages from Shawne ... which made the friend fear for Shawne's safety.

But when cops arrived to the room ... we're told they talked things out with Shawne and quickly concluded he did not pose a threat to himself or others.

Sources tell us Merriman also denied sending any texts about harming himself.

We spoke with Shawne's rep ... who told us, "It was an over-reaction on the part of whoever called. Shawne was fine."

The rep adds, "He had taken some cold medicine and was having breathing issues ... Shawne's physical safety was never in jeopardy."

Lindsay Lohan is due in court this morning for her penultimate probation progress report hearing -- and Judge Stephanie Sautner is expected to give the actress yet another glowing review.

After today, Lindsay has one more probation progress report hearing in March -- after which her probation will be terminated ... and Lindsay will be a FREE WOMAN.

The hearing is scheduled to begin at 10AM PT.


9:37 AM PT: Lindsay just showed up wearing a trench coat and sunglasses -- her mother Dina in tow.

Barack Obama once again proved he's the most qualified candidate in the field ... TO SING ... 'cause El Presidente once again flexed his voice during an impromptu blues session with B.B. King -- and it was AWESOME!

It all went down at an event at the White House last night ... when Obama went to thank King and Mick Jagger for performing ... and B.B. talked Obama into joining the gang on stage.

Then -- the guy who impressed with Al Green's "Let's Stay Together" -- began singing along to "Sweet Home Chicago" ... and KILLED IT.

And as the band played him off, Barack and Michelle made their exit ... like frickin' rockstars.

The last time Obama sang​, Mitt Romney attempted to counter​ with a rendition of "America the Beautiful" ... and sucked.

So, we gotta ask ...

There's a big, fat problem on the set of "Biggest Loser" -- TMZ has learned nearly all of the remaining contestants have walked off the show and are threatening to quit after learning about a secret "twist" that could seriously affect their shot at the $250,000 grand prize.

Multiple sources connected with the show tell us ... the mutiny took place this week ... when the losers got word that producers were considering bringing back previous contestants to compete for the grand prize.

We're told most of the current contestants were pissed -- feeling it was unfair that prior losers would get a second bite at the apple ... so they banded together and decided to protest by walking off the show in the middle of shooting an episode.

Sources tell us ... show honchos have shut down production for at least a week while they figure out how to handle the situation.

We've reached out to "Loser" and NBC for comment -- so far, no response.