Title--- Pops and the Flushed Pets

Question--- How come Pops knows the Viper and the Flushed Pets?

Answer--- Pops used to be a Flushed Pet himself.

Evidence--- His paralyzed hind legs.

Theory--- Pops used to have a different owner. But when he lost the feeling in his back legs, his owner took him and abandoned him on the streets of New York City. Eventually, the basset hound came across the Flushed Pets and joined them. During his time with them, he became very good friends with the Viper, going so far as to call him Red. But then one day, Pops was captured by animal control and taken to the pound, where he was later adopted by a man named Steve Cabin. Yet he still remembered the Viper and the other Flushed Pets.

Unanswered Questions--- Who was Pops' original owner and why didn't the Flushed Pets come rescue him?