Jeff Lacy signs to fight Nick Diaz in Boxing match in late 2011

If you call them out, they will come.
In the case of former super middleweight world champion Jeff Lacy, he'll sign on the dotted line, which is exactly what he did earlier today for a boxing match later this year.
From the official press release:

A few moments ago, former IBF super-middleweight champion & devastating knockout artist, Jeff "Left Hook" Lacy, officially signed on the dotted line to square off against Diaz in the Fall of 2011.
Lacy possesses the type of dangerous punching power in both hands that can end the double digit win streak of the rugged Northern California champion.
Don Chargin states, "This is a very dangerous fight for both men. Not only is this fight dangerous but stylistically it is very intriguing. I expected more resistance from fight fans and media in regards to this match-up but its amazing as to the hundreds of calls and e-mails I've received from fans on both sides wanting to see this match-up take place. I've received more than a few inquiries from some other very high-profile boxers that want to step up and fight Nick. Its been a real whirlwind."
Chargin continues, "I've been around boxing for quite some time and I've seen a lot of great, tough fighters in my six decades within the sport. I believe that if Nick had been one of those kids who had picked up boxing from a youth, he'd undoubtedly be a world-champion today. Sometime within the next 2 weeks I'll be personally making the trek to Cesar Gracies gym to setup a private, closed door sparring session between Nick and a few nameless top-level contenders I have in mind."

Diaz is coming off one of the craziest opening rounds in MMA history, when the scrappy Stockton slugger scored an improbable come-from-behind victory via first round technical knockout over British striker Paul "Semtex" Daley back on April 9.

Following his Strikeforce win, The Cesar Gracie student told HDNet he "doesn't see much of a future for himself in the sport of MMA" and "he's better than all the guys Strikeforce has." So why not test his much-heralded stand-up against the boys in boxing?
Now he's got an opponent. But what about a certain UFC welterweight champion that needs an opponent of his own for later this year?

Following UFC 129 this past Saturday, April 30, 2011, questions abound regarding the state of the 170-pound weight class.
The prevailing theme is that there are no fresh challengers for Georges St. Pierre and a move up to the middleweight division is imminent -- unless contracts can be worked out for a crossover superfight against Nick Diaz.
As recently as just a few days ago, the Stockton native made his feelings known on the potential bout, saying, "Let me get in there with that guy. ... What do you think is going to happen when they put him in there with me." e also makes clear one extremely important fact in all this: Diaz just wants to get paid. Whether that be an MMA superfight against St. Pierre or a big time boxing match against Lacy.