MEXICO CITY -- UFC president Dana White isn't interested in seeing Kelvin Gastelum at welterweight anytime soon.
Gastelum (11-1) earned a second-round TKO finish over Nate Marquardt at UFC 188 on Saturday. The bout was contested at 185 pounds.
It was Gastelum's first appearance at middleweight since he won "The Ultimate Fighter" reality series in that weight class in April 2013. The 23-year-old had fought his previous five fights at welterweight, compiling a 4-1 record.
Gastelum, however, struggled to make the 171-pound weight limit. He failed to make weight twice, including a nine-pound fiasco prior to UFC 183 in January. At that time, White made it clear that Gastelum's next fight would take place at middleweight. Apparently the UFC boss hasn't changed his opinion.
"I love this kid," White told ESPN.com. "He's such a great fighter. His standup looked great tonight, but I don't believe he can make 170. I honestly don't. He's done nothing to prove he can make 170 pounds, and when he doesn't make 170 pounds, it's dangerous and it screws a lot of things up around here.
"He didn't look like he was going to die at weigh-ins -- and he fought great tonight. So, if you're me, or anybody who even remotely cares about the kid, where would you have him fight? I get he wants to make it to 170, but he's going to have to do something. Just training and doing what he's doing isn't cutting it."
Gastelum, who fights out of Alliance MMA in San Diego, has said he feels too small to be truly elite at middleweight. After hearing White's comments, he said he'd do whatever it takes to prove to the UFC he can consistently make 170.
"Like he said, I haven't done anything to prove it," Gastelum said. "Actions speak louder than words. Now that he's said I just need to prove it, I'm going to prove it."