Skarlatos snapped a selfie with Spencer at his bedside on Saturday at UC Davis Medical Center, and captioned the pic: "Saw the hero today." He later took down the image.
The men are two of the three American heroes that helped take down a gunman on a Paris-bound train from Amsterdam in August.
Stone, 23, was stabbed three times during a fight outside a Sacramento nightclub. After undergoing surgery, he is now in fair condition and expected to make a full recovery. Police are still searching for the people connected to the stabbing.
In another Instagram post, Skarlatos wrote: "Send some prayers out the the guy in the middle @spencthang."
The Sacramento Police Department told ET that they received a call from a passerby that a subject had been stabbed, and he was located on scene and transported to an area hospital by fire personnel. It is believed that Stone was out with a group of friends when a physical altercation led to him being stabbed multiple times in his upper body.