The pair had been scheduled to face-off in Los Angeles in March, only for the Texan to pull out of the bout just days before it was set to take place having been hospitalised with a serious condition.
Questions had been raised whether Ortiz Jr - 18-0 as a pro with all of those victories coming by knock-out - would fight at welterweight again, as making 147lbs appeared to be an issue which led to his hospitalisation.
However, an agreement has been reached for the Pompey Problem to head back out to the States on August 6 to take on Ortiz Jr at the Dickies Arena, Fort Worth, Texas.
Following the American's late withdrawal, McKinson - himself unbeaten as a pro with a 22-0 career record - finally managed to find an opponent at late notice, defeating Alex Martin at the Los Angeles Galen Centre.
But the rescheduling of his welterweight showdown is the potential life-changing shot McKinson has longed desired.
Speculation had surfaced that Ortiz Jr would face EBU European champion David Avanesyan for his comeback fight, with the Texan having now not fought since August last year after his late withdrawal from the previously planned battle with McKinson.
Yet that did not come to fruition, with McKinson now primed to attempt to cause a major upset and propel himself onto the world scene against one of American's most highly rated stars.