Jeff Horn is exploring his options after Manny Pacquiao dropped out of a rematch planned for Brisbane in November.

Former two division champion and current welterweight contender Jesse Vargas has emerged as a potential replacement. Vargas could fill the void left by Pacquiao to fight Horn for the WBO welterweight title in Brisbane later this year.

Pacquiao's withdrawal from a planned November rematch was announced on Friday, due to his commitments as a Philippines senator.

The Australian defeated Pacquiao in July's "Battle of Brisbane" to snatch the world title in a famous upset before a crowd of 51,000 at the Suncorp Stadium. The fight drew a television monster rating on ESPN.

And the second instalment seemed set after the Filipino fighter's initial promise to return later this year. There was an immediate rematch clause at Pacquiao's disposal.

But after a period of uncertainty surrounding the fight, Horn's promoter Duco Events confirmed on Friday that a 2017 rematch was not possible.

"On behalf of the Philippines government he will be part of a delegation that will visit China in the middle of his proposed preparation period for the fight," Duco Events director Dean Lonergan said in the statement.

"Pacquiao is committed to fighting again in 2018 and a rematch with Jeff Horn for the WBO world welterweight title.

"Until then ... we will be exploring options."

The Queensland Government stated on Friday it would support Horn's title defence regardless of the opponent.

 Vargas, who Pacquiao beat in a unanimous decision before the Horn bout, shapes as a worthy replacement.

Vargas previously held the WBA world title at 140-pounds and then knocked out Sadam Ali last year to capture the vacant WBO title, which Pacquiao captured from him a few months later.

Like Pacquiao, the Las Vegas-based boxer is in Bob Arum's Top Rank stable and his chance to retain the title could be viewed as the perfect alternative.