T-1000 actor Robert Patrick didn’t appear in James Cameron’s original The Terminator was a hybrid of sci-fi and horror that followed Arnold Schwarzenegger’s titular villain, an android assassin, who traveled back in time to kill a resistance leader before they were even born.
Cameron flipped the script with 1991 sequel Terminator 2 wherein the Terminator was now the hero and the villain was an even more dangerous killer; Robert Patrick’s lithe but lethal T-1000. A more advanced Terminator model, the T-1000 was able to melt into liquid metal and reform itself, a terrifying new ability that rendered this new breed of the eponymous villain more threatening than ever. In the movies that followed, the female T-X of Terminator 3: Rise of the Machines and other lesser additions struggled to outdo the implacable, icy T-1000.
However, despite the T-1000’s enduring popularity among audiences, the actor never returned for later installments. Patrick did say during a roundtable interview with Terminator: Genisys the T-1000 was played by actor Lee Byung-hun. The reason Patrick didn't appear was likely because Genisys recast most of the franchise's most famous characters, and because the actor had earlier said he didn’t want to play the role again as advancing age meant certain stunts would be less practical for him.
In early drafts of Terminator: Salvation’s un-produced sequel, Patrick would have played the human scientist who developed the original T-1000 in his image, a less physically demanding role the actor could have taken on despite his advancing years. However, when the T-1000 appeared in Genisys, the villain had a new face like fellow recast characters Sarah Connor, Kyle Reese, and John Connor. Patrick made it clear in a Huffington Post interview prior to Genisys that having done a lot of his own stunts in Terminator 2, he wouldn't want to sully fan’s memories with the limited stunt work he’d be able to perform, saying: "I’ve got a bad hip now, I’ve slowed down quite a bit so." He also added, "I don’t know if it would be to my advantage to revisit it." It was just as well the actor wasn't part of the production, since Genisys's Sarah replacement Emilia Clarke went on to fracture her own hip making it.
The cause of the Terminator 2 villain dodged a bullet by avoiding an appearance in Genisys, which went on to receive some of the franchise’s worst reviews. Terminator: Genisys is arguably the weakest of the franchise, and it's doubtful a Robert Patrick appearance could have done much to help.
