By Andrew Gould Colin Kaepernick is striving for an NFL comeback. The former San Francisco 49ers quarterback announced that intention to the world by sharing a workout video on Thursday, but he can only do so much preparation on his own. On Sunday afternoon, the 34-year-old posted an open call for “professional route runners” to work with him. “For The past 5 years I’ve been working out and staying ready in case an opportunity to play presented itself,” Kaepernick wrote on Twitter. “I’m really grateful to my trainer, who I’ve been throwing to all this time. But man, do I miss throwing to profe…