Sammy Vasquez Jr. was hoping his last opponent would provide the toughest challenge of his fast-rising career. It didn’t work out that way, but “The Sergeant” may get his wish with his next foe.

Sammy Vasquez Jr. delivers a straight left hand at Aron Martinez in January. The unbeaten Vasquez battered Martinez for six rounds en route to his 10th stoppage victory in his last 12 fights. (Suzanne Teresa/Premier Boxing Champions)

Sammy Vasquez Jr. (21-0, 15 KOs) will return to the ring for the first time in nearly six months when he puts his unbeaten record on the line against former world champion Luis Collazo (36-7, 19 KOs) on July 16 in a 147-pound clash of southpaws.

The contest, which is scheduled for 10 rounds, will precede heavyweight champion Deontay Wilder’s title defense against Chris Arreola from Legacy Arena in Birmingham, Alabama (Fox, 8 p.m. ET/5 p.m. PT).

Following a trio of one-sided victories in 2015, Vasquez kicked off the new year on January 23 with a fight against Aron Martinez, who was coming off a stunning upset of former champion Devon Alexander. Given that result, Vasquez was expecting his most difficult fight of his career, but instead the 30-year-old native of Monessen, Pennsylvania, walked right through Martinez.

After absorbing a ton of abuse, Martinez quit after six rounds because of an arm injury. That gave Vasquez, who served two tours of duty in Iraq with the National Guard, his 10th stoppage in his last dozen bouts dating to August 2013.

“This is a great opportunity for me, and I’m looking forward to showcasing my talent and skills,” Vasquez said. “Luis Collazo is one of the toughest guys I’ve fought so far, and he’s definitely going to test me.

“My job is to go in there, handle my business and beat him worse than anyone else has. I think our styles will combine for a great battle, and I’m excited to give the people another great fight.”

Collazo became a 147-pound world champion in April 2005 when he won a split decision over Jose Antonio Rivera. He successfully defended his crown in his next fight—a seventh-round stoppage of Miguel Angel Gonzalez—but is just 10-6 since then, with five of those losses coming against current or former world champions.

That includes his most recent bout last July, when Collazo fell to 147-pound champ Keith Thurman. Collazo nearly dropped Thurman with a vicious body shot in Round 5, but Thurman stayed on his feet, went on the attack and opened a cut over Collazo's left eye, leading to a seventh-round stoppage.

It was just the second time in Collazo’s career that he’s been stopped, the other coming to Edwin Cassiani in April 2002 in his first defeat. Collazo, a 35-year-old New York native, has won five of his last seven contests, the only setbacks coming against Thurman and former 140-pound titleholder Amir Khan.

“I’m totally stoked about this fight against Sammy Vasquez,” Collazo said. “He is a talented fighter, and I’m excited to test his abilities and the will that he has to keep that zero. This will be a good one.”