Friday night, John Molina’s career is more or less on the line as he meets unbeaten Mickey Bey in their ShoBox-televised ten-round main event in Las Vegas.

Coming off a close decision loss to Andrey Klimov just north of a month ago, Molina has switched trainers, from Oxnard, Calif.’s Robert Garcia to 45-minutes east in Van Nuys with Joe Goossen.

This will mark the third time Molina and Goossen have linked up. The two have been more on-again, off-again than Ross and Rachel of ’90s sitcom Friends fame.

“I didn’t watch Friends, so I’m not familiar with that reference, but how about more than Liz [Taylor] and Dick [Burton]?” asked Goossen on Wednesday, when asked about the renewed vows.

“I’ve got an eight-month old at home and the back-and-forth to Oxnard was tough on me,” shared Molina on why he switched from Robert Garcia back to Goossen.

Molina turned pro under trainer Ben Lira before switching to Goossen in December of 2008. It was Joe who alerted older brother Dan Goossen to Molina’s talents, urging him to take a look at the young Covina, Calif., fighter. Goossen-Tutor signed Molina to a deal soon after.

Molina suffered a wide points loss to veteran gatekeeper Martin Honorio on ShoBox under Goossen back in November of 2009, though both fighter and trainer claimed he had the flu and was far from 100 percent.

Eight months later, Goossen was in the corner for Molina’s signature win, where he stopped undefeated Hank Lundy in the 11th round while far behind on the scorecards in their ESPN2 Friday Night Fights main event.

Goossen wasn’t a stranger to comeback victories; he cornered perhaps the greatest single-round comeback of them all. In May 2005, Goossen implored his fighter Diego Corrales, “You gotta f—-in’ get inside on him now!” after he was dropped twice in the 10th round by Jose Luis Castillo in their lightweight unification bout.

Corrales got up, and proceeded to bash Castillo against the ropes, stopping him on his feet in what was maybe the best 135-pound fight in boxing history.

Having endured the Honorio loss to earn the win over Lundy, it seemed as though fighter and trainer were on the same page.

That’s why it was such a surprise when Molina ditched Goossen for trainer Mario Morales in 2011.

“Honestly, that was the time we should’ve kept things going,” said Goossen. “We had a lot of momentum, and it just didn’t make sense to me. But it is all water under the bridge.”

The loss was hearbreaking at the time for Goossen, though he wasn’t a stranger to those kinds of circumstances.

Goossen’s gone back to fighters who have left him a number of times, most notably Michael Nunn and Joel Casamayor, two fighters with whom he had a large hand in their success.

Goossen just doesn’t seem to be able to learn. The old, “Fool me once…” idiom hasn’t caught on with the veteran trainer.

But never before has he been lured back for a third time.

“Listen, John is a good kid, and I like him and his family a lot,” said Goossen. “If it were someone else, maybe I wouldn’t be working with him. But in Washington, after his loss, we sort of bumped into each other at one of the restaurants and started talking about his fight that night, and it just spiraled from there.”

Goossen is hoping the third time with Molina can enact a different ending in a story that the trainer has thought was a Choose Your Own Adventure type, but has instead played out as a direct read-through.

That Molina has switched trainers more than most people change their socks is an alarming sign. Both times he left Goossen, he claimed it wasn’t personal, but that he felt it was the best move going forward.

“Listen, you know how it is with some friends you might have,” reasoned Goossen. “Everyone has those friends that, every now and then you get into these little beefs with, but they are people you’re always going to stay close with.”

“Joe and I have always had a good relationship outside of the ring, and when I came back to work with him, things picked up in the gym right where they left off,” said Molina.

What makes it doubly interesting that with his career on life support, Molina has turned to the familiar to help revive it.

In their second incarnation, Goossen rejoined forces with Molina and led him into a 135-pound title shot against rugged Mexican Antonio DeMarco on the Andre Ward-Chad Dawson HBO undercard.

Forty-four seconds after the opening bell, Molina’s title challenge was over. DeMarco hurt him early, forced him into the corner, and battered him until referee Jack Reiss had no choice but to stop the fight.

Goossen saw his fighter shellshocked, perhaps due to being on the big stage for the first time. Though it may not have changed the outcome, his fighter could have taken a knee in order to preserve himself a bit longer in the fight.

The humbling defeat drove Molina to join up with Garcia in Oxnard. Things looked promising after Molina gave his career a bit of life after stopping Dannie Williams in four rounds in January on ESPN2. A close majority-decision loss to unbeaten but largely unknown Andrey Klimov on the same network in June took Molina off the rails yet again.

Molina now finds himself in a tough spot. The fight with Bey is a true crossroads bout, almost to the definition.

Both fighters are 30 years old, though Molina has faced the far superior opposition to his undefeated foe. Bey is looking to shake off the criticism that came with the positive drug test that followed his brutal KO of Robert Rodriguez in February.

“The key thing I take from that situation, is for a guy to allegedly increase his testosterone ratio that much to fight a 7-2 fighter, that says a lot about someone,” said Molina. “It tells me he is a bit insecure.”

“I know they were hesitant in taking this fight, and I am surprised they took it,” continued Molina. “I am going to bring a lot of pressure and get started much earlier than I normally do.”

A loss for Molina undoubtedly would relegate him to gatekeeper status, whereas a victory could position him for another run at a title shot in a thin 135-pound division.

“Everyone knows that any fight I am in is usually a fun one, so a win here and I figure I am right back in the mix to get back into the big fights.”

With Goossen and Molina reunited, it would be an interesting plot-turn in a story that has seen many twists.

Photos: Tom Casino-Showtime; Mark Ralston-AFP/Getty; Naoki Fukuda

Mark E. Ortega is a contributing writer to RingTV.com and has been featured in boxing publications RING Magazine and Boxing Monthly. He is a member of the Boxing Writers Assoc. of America and can be reached via e-mail and followed on Twitter.