AURORA — The 6-foot, 231-pound NFL linebacker sat quietly on the leather bench inside the first floor of Children’s Hospital Colorado. His navy T-shirt and shorts tried to mask his identity, but soon he would stand out.



As parents, nurses and physicians strolled by, each gave a squint of curiosity — Who is that? — as he slipped on his bright orange No. 43 Denver Broncos jersey and grabbed an outsized duffle bag adorned with the Broncos’ logo.



“I’m ready,” he said. “Let’s go.”



With the bag stashed in a red Radio Flyer wagon, he walked into the elevator and got off on the fourth floor, home to the neonatal intensive care unit (NICU). After a debriefing by a hospital official, he doused his hands in sanitizer before slipping on a yellow isolation gown, blue latex gloves and a surgical mask.



From the duffle he pulled out a navy drawstring bag with a Broncos teddy bear inside and slowly...