The Thai has long been linked to a bout with former WBC champion, and current WBA interim champion, Xiong Zhao Zhong (27-7-1, 14) [熊朝忠], though from the reports it sounds like Rojas' team have decided not to take any form of step aside payment and will instead force the mandatory between their man and the Thai, who beat Rojas to unify the WBA "interim" and regular titles back in 2016.
Since beating Rojas we've seen Knockout reocrd 4 straight wins, defeating Shin Ono, Go Odaira, Rey Loreto and Toto Landero. At times he has impressed, with his win over Loreto being a very solid performance, be he was underwhelming last time out, against Landero, and would need a much better performance to defeat Rojas against.
As for Rojas, who won the title against Hekkie before losing it to Knockout in his first defense, fans in Nicaragua have seen him reel off 7 straight wins, though they have all been against relatively under-whelming foes in Nicaragua. The most recent of those came last December, in what was Rojas' 6th bout of 2017, and saw him struggle past Byron Castellon with a majority decision.
The bout is now sounding like a done deal, and is likely to be announced in the very near future with a specific location likely to be tied down in the coming weeks.