Danny Jacobs (R) vs. Keenan Collins on April 27, 2013. Photo by Elsa/Getty Images.

BAYAMON, Puerto Rico – Danny Jacobs was stunned to find out that not many people knew that he was fighting on the undercard of the Danny Garcia-Mauricio Herrera show at Coliseo Ruben Rodriguez on Saturday night.

But he’s happy to be getting back in the ring to pick up on his quest to become a middleweight champion. Jacobs will fight Milton Nunez (26-9-1, 24 KOs), a journeyman from Miami, in a bout that will be broadcast on Showtime Extreme.

“I’ve had my highs and lows and I’ve kept trucking. This is one of those things where I have to fight Milton Nunez, which some would consider a journeyman, and get over him and see what the future brings,’’ Jacobs said. “I wanted to stay as active as possible, especially since I’ve been off for a very long time.’’

Jacobs (26-1, 23 KOs) was diagnosed with osteosarcoma, an aggressive form of cancer that manifested itself as a walnut-sized tumor wrapped around his spine, in May 2011. The tumor had damaged his nerves and caused partial paralysis in his legs. Doctors advised him to quit boxing. But after having the tumor removed and going through rehabilitation, Jacobs resumed training.

He returned to the ring on Oct. 20, 2012, scoring a first-round knockout against Josh Luteran in the inaugural boxing show at Barclays Center in Brooklyn.

“I’ve had some fights since then and I’ve been gradually getting better and better. I wanted to stay active to keep that flow going,” Jacobs said.

Jacobs has fought three times since that comeback win against Luteran. He has worked himself back into contention.

“This is his first fight of 2014,” said Eric Gomez, Golden Boy Promotions chief matchmaker. “He’s been off for a while. He hasn’t fought since August. There are a couple of fights that fell through. This fight [against Nunez] is just maintaining and getting back in the groove. After this fight he’s ready for a title fight. He wants to fight Peter Quillin or any of the champions. We’ll see how he does on Saturday. But this is just a fight to get him back in the swing of things. A maintenance fight.’’

Jacobs said he has been frustrated with not getting the Quillin match, which is a natural for Barclays Center considering both of them are known quantities in New York and have fought at the arena. Jacobs lives in Queens and Quillin, the WBO middleweight champion, used to live in Brooklyn.

“It’s definitely makeable. We’ve got the same manager and promoter,” Jacobs said. “We know the battle that’s going on between the two networks. It’s an easy fight to make in a place where the fans want it. I’ve never had so many fans on InstaGram and Twitter that want to make this fight. This is just not me calling out someone or looking for just any champion. This would be a fight that the fans want and they’re going to get it soon enough.’’

Andre Rozier, Jacobs’ trainer, said it has been extremely frustrating trying to get Quillin to agree to a fight.

“It’s incredible. We were looking to box Peter in January. That didn’t happen,” Rozier said. “It’s been a long drawn out process. We still don’t know if they’re going to get in the ring against each other. I don’t think Pete wants the fight. Danny wants it in the worst way. It’s a rough place to be in. Waiting, expecting, anticipating.”

Jacobs left New York in January and traveled to Australia to stay with friends and train. He was gone for over a month and it gave him a new perspective on things. And it wasn’t because he was halfway around the world.

“I had a chance to work some fitness guys and got a chance to learn some different techniques on boxing and training,’’ Jacobs said. “It opened my mind on different aspects of how far I can take my training to be a better me. I was there for a whole month. I had to gain weight when I came back so I could put it on and lose it again.’’

If Jacobs can’t get Quillin in a championship fight, Rozier wants him to stay busy, thus the match against Nunez.

“I’d like to keep him moving every three months,’’ Rozier said. “I’d like to see my guys box a lot. That’s the only way you maintain your skill level. I’d like to see him pick the pace up. It’s not like, ‘I’m Floyd Mayweather and I’m boxing twice a year.’ He’s in the stages of ‘let me work.’ If I could get him work five times a year, I’d like to do that.’’