Gunnar Nelson uncertain Conor McGregor returns to UFC in 2017

Gunnar Nelson says a potential Conor McGregor vs. Floyd Mayweather fight "seems like it's going to happen." Jeff Bottari/Zuffa LLC/Getty Images

A proposed boxing match against Floyd Mayweather would obviously have a profound impact on Conor McGregor's net worth.

Here's a question, though: What impact would that massive payday have on McGregor's future in the UFC?

McGregor, 28, is coming off a 2016 campaign in which he fought three times and earned around $40 million (according to his estimates). Should this long-discussed boxing match with Mayweather come to fruition, he would likely exceed last year's figure in a single fight.

How motivated would the Irish star be to return to the UFC after such an event? UFC welterweight Gunnar Nelson, a longtime friend and training partner to McGregor, offered his guess to ESPN.com.

"It will depend on certain things," said Nelson, when asked if McGregor would ever fight in the UFC again. "Money is not the only thing he cares about, at all. He does care about it a lot, but if a fight excites him and he thinks it's a great challenge -- if it's making history and all that kind of stuff -- he'll do it."

Momentum behind the Mayweather-McGregor fight has been on a constant rise in 2017. Last month, UFC president Dana White, who had long been skeptical of the bout, significantly changed his tune by saying, "I just don't see how it doesn't happen."

Mayweather has publicly called for the fight to take place in June. McGregor has countered by mentioning a potential date in September.

McGregor (21-3), who won the UFC lightweight championship in November, has been extremely active since signing with the UFC in 2013.

When asked if he believed McGregor could go an entire calendar year without a fight if negotiations took longer than expected, Nelson felt he could.

"He's got a lot of money now that keeps him occupied," Nelson said. "He can do a lot of stuff. I think he'd be all right for a year. He always has something cooking. Right now, it's the Mayweather fight, and that seems like it's going to happen. I think he'll keep himself busy one way or another."

In a recent interview with the Irish Mirror, McGregor's head coach John Kavanagh suggested McGregor "isn't going anywhere soon."

Nelson seemed to agree. But even if a Mayweather fight wouldn't cut short McGregor's potential UFC career, it could dramatically affect which fights ultimately interest him.

"He needs to keep himself busy in some way, because he's a pretty hyper guy," Nelson laughed. "He's not just sitting around the house. If he wouldn't have anything to do, he'd probably be up to no good. He'll always figure something out. He needs excitement."