Kelvin Gastelum looked dominant in his win over Nate Marquardt at UFC 188 on Saturday night, but the future for The Ultimate Fighter winner is a bit uncertain.

Sure, he's got a future in the UFC, but at what weight class? Gastelum defeated Marquardt in the middleweight division after being forced to compete there following a badly botched attempt to make welterweight against Tyron Woodley in January of this year. That marked the second time Gastelum has failed to make welterweight in his six welterweight UFC fights.

According to UFC president Dana White, Gastelum is well liked, but isn't going back to welterweight any time soon.

"Well, you know, I love this kid. He's such a great fighter," White told the media at the UFC 188 post-fight press conference. "First of all, he goes in with a kid like Marquardt and stands right in the pocket with him and exchanges. His stand-up looked great tonight, but I don't believe he can make 170. I honestly don't believe he can make 170.

"He's done nothing to prove he can make 170 pounds," White continued. "And when he does make 170 pounds, a) it's dangerous, and b) it screws a lot of things up around here. He's going to have to get serious and get a nutritionist. He had to cut to make 185 and he came in right on the nose. I am the furthest from confident that he is capable of making 170. No matter how much I like him or how much he says he can do it, I don't believe it."

White didn't say Gastelum can never go back to welterweight, but until he meaningfully proves he can to White's satisfaction, Gastelum's future resides at middleweight.

Besides, White noted, Gastelum performed very well in his UFC middleweight debut.

"He made 185 and he looked great at 185. He looked healthy. He didn't look like he was going to die at the weigh-ins, and he fought great tonight. So, if you're me or anybody who even remotely cares about the kid, where would you want him to fight? At 185," White said. "I get it. He wants to be at 170, but he's going to have to do something to get to 170 and just training and whatever he's been doing hasn't been cutting it."

Gastelum seemed understanding and compliant. When asked for a response to White's concerns, Gastelum said he shared them, but intended to prove he can do what White thinks -- right now -- that he can't.

"Like he said, I haven't done anything to prove it," Gastelum admitted, "but actions speak louder than words. Now that he said I just need to prove it, I'm going to prove it. That's fine."

White followed Gastelum's statement with a reminder of what the effects have been with the fighter's failed weight cuts and why it can't be risked again.

"He's proven he can make it, but he looks like he's about to die when he makes it," White said. "And he's gotta go back and try it one more time, you know what I mean, to come back and make the weight.

"It's not healthy," he said. "It's not good for him and it's definitely not good for us."