By Jake Donovan

For Mikey Garcia, this weekend marks what is literally the biggest fight of his career.

The four-division titlist from featherweight through super lightweight looks to conquer a fifth weight division as he challenges unbeaten welterweight title claimant Errol Spence Jr. Their Fox Pay-Per-View headliner takes place this Saturday at AT&T Stadium in Arlington, Texas, mere minutes from Spence’s Desoto hometown.

A pair of fights at 140-pounds were as high as Garcia (39-0, 30KOs) has been in his career, but didn’t even stick around long enough to call it his most recent home. The 31-year old Californian dropped back down to lightweight for his last bout, a 12-round title unification win over previously unbeaten Robert Easter Jr. last July.

He enters this weekend as the considerably smaller fighter; just don’t mistake him for a small fighter.

“We did all the work with Victor Conte and the SNAC team, putting together the right plan to add the right amount of muscle and mass,” Garcia noted during a recent media conference call of the lengthy training regimen that actually saw him bulk up heavier than expected. “I was up to 160 at one time. As we began training and sparring, we noticed I was too big too early.

“So, we started to get more sparring and training and that extra bulk started coming off right away because that’s what comes with hard work.”

Garcia wouldn’t tip his hand as to how much he expects to officially weigh on Friday. Spence (24-0, 21KOs) has never weighed lighter than 146¼ pounds, which is what he officially checked in at ahead of his welterweight title-winning knockout of Kell Brook in May ’17.

The undefeated southpaw has since made two successful defenses, coming in at the 147-pound limit for an 8th round knockout of former two-division champ Lamont Peterson and 146¾ pounds for a 1st round stoppage of Carlos Ocampo last June.

Meanwhile, Garcia will fight above 140 pounds for the first time. In fact, he weighed 139½ pounds for each of his two super lightweight encounters, both resulting in decision wins over Adrien Broner and previously unbeaten titlist Sergey Lipinets, respectively.

Still, he didn’t take this fight just to get into a weigh-in contest with Spence. Nor is it believed amongst his team that anything other than what takes place from bell to bell will dictate the outcome of Saturday’s fight.

“I’m naturally a smaller guy. So you have to build a little more mass and a little more muscle building up to this fight,” Garcia acknowledges. “But we don’t plan to beat Errol Spence just with mass and muscle. I don’t want to move up and just look sluggish. We plan to beat him with my hands and my feet.

“Everything has been done the right way and we’re very pleased with the results. We got all the sparring in with big guys that could really push me. We also worked with faster welterweights just so that I could be quick and explosive. You don’t just win fights by being the bigger fighter in weight. I took this fight to challenge myself.”

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox