BRISBANE - WBO welterweight champion Jeff Horn is eyeing a title defense against former two division world champion Jessie Vargas after Manny Pacquiao's decision to postpone their planned rematch.

"I'm frustrated. I'm kind of annoyed that it's taken this long to make a decision but, look, that's boxing, I'm figuring out that now. That's what happens at the top of the game, guys mess around with you a lot," said Horn.

Pacquiao, a senator in the Philippines, has pulled out of his proposed November 12 bout with Australian Horn for the WBO welterweight title because of government duties. The Filipino star is a senator in the Philippines.

Horn (17-0-1, 11 KOs) upset Pacquiao for the WBO welterweight title in a unanimous 12-round decision in Brisbane, Australia, on July 2.

There was a rematch clause in place, with Pacquiao exercising his right to get an immediate second fight. He tried to challenge the scoring of the first bout, but the WBO investigated and deemed Horn as the rightful winner.

The proposed rematch in Brisbane had been confirmed by both camps on Aug. 21. The fight was expected to be held at the same outdoor stadium in Brisbane where a hometown crowd of 51,000 saw Horn, a former schoolteacher, stun Pacquiao for the WBO welterweight belt.

Vargas, who is based in Las Vegas and former champion at junior welterweight and welterweight, could possibly take Pacquiao's place for a fight later this year against Horn, the promoters said.

Vargas has been out of the ring since November of 2016, when he lost a twelve round decision and his WBO title to Pacquiao. Vargas, like Pacquiao, is promoted by Top Rank, who also have rights to the next few fights of Horn.

"Yeah, [Jessie] Vargas is a fight that we'd definitely take. He's a tough competitor and he's been world champion, he's held my belt just before Pacquiao, so he'd definitely be a tough fight and worthy opponent," Horn explained.