From the Salt Lake Tribune's Ross Siler, via his twitter feed:

I thought of the name last night and somebody seconded it this morning - - Mark Madsen - - now that the Utah Jazz are looking for a 13th man.
Madsen has spent this season as an assistant coach with the D-League's Utah Flash, who run the Jazz's system and everything.
He fits the bill as the veteran 4/5 the Jazz probably are looking for with their open spot.

While I think this was mostly in jest, it really does kind of make sense because, as Siler says, Madsen knows the system and fills a need. 

The 34-year old Madsen has played in 453 NBA games, including 49 during the playoffs, and would bring a wealth of knowledge and a veteran presence to the hopeful playoff team.

"[...] He's as good a big man as we have,"said Utah Flash head coach Brad Jones.

Madsen, though, gave Jones his word that his playing days were done. "I said, 'If I make a commitment, I make a commitment,' " Madsen said.

Seems, judging from this Siler article that Madsen has put the kibosh on playing again.

Anyway, I'll have a story up soon on who the Jazz should call-up (Preseason invitee Alexander Johnson or dominant big man Dwayne Jones probably lead the way), but this would certainly be an interesting alternative.

As an aside, what would make more headlines?  The Flash's assistant coach getting a call-up to play in the NBA or the time they brought a fake Michael Jordan impersonator to their game?