Some would say what Jeff Curran is embarking on is ambitious. Others might call it downright nuts.

At 35, Curran (35-15-1) has fought under just about every major MMA banner imaginable, including the UFC, WEC, Bellator, Strikeforce, PRIDE, the IFL and others. But next week, the suburban Chicago-based Curran returns to the promotion that gave him his MMA start: Extreme Challenge, one of the longest-running promotions in MMA.

But the part some may find to be a little crazy is that Curran will do it at flyweight.

Fighters drop weight classes all the time, of course. And given Curran’s been at bantamweight for three years, dropping down, on the surface, doesn’t seem that big of a deal. But consider that he’s a longtime featherweight who also has fought at lightweight as recently as November 2009, and it’s easy to raise an eyebrow at the prospect of him getting down to 125 pounds.

After all, the dude’s nickname is “Big Frog.” But now, as he says, he’s not so big at all.

“At 35 years old, it isn’t easy to just change lifestyle and eating habits to venture into the unknown,” Curran told MMAjunkie.com (www.mmajunkie.com). “But I am, and I’m loving it – 125 is where I belonged my whole career, I believe. I’m really little now.”

Curran’s flyweight debut takes place May 3 as part of Extreme Challenge 227 in Bettendorf, Iowa. He fights Josh Killion (8-4), a 20-year-old Midwesterner who is unbeaten at flyweight and has won four straight.

To put No. 227 in perspective for Extreme Challenge, longtime manager Monte Cox’s promotion, Curran’s first pro fight was in 1998 at Extreme Challenge 13. But while Curran is returning to his roots for this one, he’s set a goal of this just being the first step on his road back to the UFC.

At UFC 46 more than nine years ago, Curran debuted in the UFC and dropped a decision to future welterweight champion Matt Serra in a lightweight bout. He then leapfrogged, appropriately, through regional shows big and small, a loss to Hatsu Hioki for PRIDE and then, ultimately, into the WEC.

There, he earned a quick shot at featherweight champ Urijah Faber‘s belt. A submission loss in the title fight was the start of a rough four-fight skid and his release. By the time he had gone 4-1 away from Zuffa, the WEC had merged into the UFC, and Curran got a call to return. But losses to Scott Jorgensen and Johnny Eduardo again sent him packing.

After that, he put a plan in place to make a run at 125 pounds, a plan that nearly went right off the rails before it even could get started.

“The initial cut was going great in the early summer (2012) before needing to undergo hand surgery on each of my hands,” Curran said. “That was a big setback. Then the day I returned to training three months later, I ruptured my LCL (lateral collateral ligament) in my knee. It was a huge test of my commitment to even want to fight again, to be honest. That lasted about a day. Then I just began to diet and do what I could until healed.”

Curran said UFC matchmaker Sean Shelby, who handles the company’s lighter weight classes, knows his intentions and knows he wants to go on a run and earn his way back into the company. That’s where he believes he should be.

“I belong there, 100 percent,” he said.

But he won’t keep him on speed dial after each fight. Instead, Curran plans to just do the work and believes the ultimate goal then will take care of itself.

“I need impressive wins to prove that the weight class is a place I can get back to finishing fights,” Curran said. “I’ll let my results do the talking this time. The UFC will need a kingpin like me in the division to thicken it up.”

Not fighting since May 2012, when he lost a decision to Eduardo, doesn’t mean Curran has been sitting idle. Far from it. His MMA school in Crystal Lake, Ill., has plenty of fighters to keep him busy coaching and mentoring and cornering, including his cousin, Bellator featherweight champ Pat Curran, Bart Palaszewski and Felice Herrig.

And to top it off, a documentary about his life in the fight game is in progress. “Martial Life” will wrap this summer. Curran said the documentary tracks him for six weeks during his first venture into the flyweight ranks, and it also includes his cornering and coaching work for Team Curran fighters.

“It will be a two-hour film, from XFC to Bellator, the UFC and local shows – all in middle of my training and weight cut,” Curran said. “It’s my life summed up. It’s an intimate look into my life and my childhood and how and why I do what I do. It’s going to be great.”

But perhaps it’s the potential sequel he would be most interested in – one that would culminate with one more crack at the UFC in the latter stages of his fighting career.