It used to matter if the shirt was Kentucky blue or Western Kentucky red.
But now, as long as the whistle is dangling around Mike Cassity's neck, the color of the shirt beneath it doesn't matter much.
"It's been about an eight-month struggle for me to get back to have the opportunity to put on a coaching hat, a coaching shirt, a hat and a whistle," Cassity said on Thursday, his 60th birthday.
"A lot has happened to me and I've overcome it."
Cassity, who coaches the secondary for the Hilltoppers, just a season removed from coaching the same position at UK, has had nearly a year full of those "why me?" moments.
In early November, Cassity was fired from his alma mater as a part of Joker Phillips' staff.
By December, he was sitting in doctors' offices having every imaginable test run because doctors believed he had cancer based on an MRI that revealed a troubling spot on his back.
It was yet another bad break that got him to that potentially life saving MRI table in the first place.
Late in November, already dismissed by UK but finishing out his contract until the end of the season, Cassity was sprinting down the practice field with the kickoff unit. He pulled up after seven yards in with a throbbing hamstring.
The former safety, who still looks like he's in playing shape even though it's been decades, did as trainers instructed, took it easy. But a few days later, the hamstring injury bled. The pain began to alter his gait, causing his hip to throb constantly.
Cassity went through weeks of chiropractors, traction and stimulation therapy before UK trainer Jim Madaleno suggested that he have the MRI to take a closer look at his hip.
That's when team doctors found the tiny black dot on Cassity's third vertebrae.
Dr. Rob Hosey asked Cassity how he was feeling. He asked if the coach was having night sweats. Had either of his parents ever had cancer? The coach had lost both his mother and father to lung cancer.
He froze for a second. "Doc, what's up?"
Hosey explained that the dark spot on the coach's third vertebrae was "very, very concerning to us."
After dozens of tests ruling out all sorts of other cancers, doctors finally diagnosed him with multiple myeloma, a cancer in your plasma cells.
Cancer. The word itself was breath borrowing.
"You don't have a job; you're fighting this," he recalled thinking. "You've got to be up front with the person who's going to hire you."
Luckily, the cancer — detected so accidentally — was in its earliest stages.
"The doctor actually said it was so, so early that I might not have known for a long time if I hadn't pulled my hamstring," Cassity said.
As this was going on, Cassity was in talks with Western Kentucky and his former boss Bobby Petrino, the new head coach there.
"Bobby, the timing might be bad, I have this issue," Cassity told Petrino, for whom he had worked at Louisville. "I told him, 'If we can't coach together right now, I understand. We'll coach together again some day.'"
Petrino would have none of it. WKU would work with him. Just get better, his new boss said.
Cassity was in for the fight of his coaching life, which included 16 brutal weeks of chemotherapy at the Markey Cancer Center. He made recruiting calls as he went back and forth from Lexington to Bowling Green twice a week.
"Ten percent is what happens to you and 90 percent of it is how you react to it," he would remind himself. It was something he regularly told his players.
After chemo was over and his blood work came back clean, Cassity had a bone marrow transplant using his own stem cells. He stayed in the UK Hospital, just blocks from the school's football facilities, for 11 days.
A few of his former players came to visit.
"He had a bald head," sophomore cornerback Fred Tiller recalled of the visit.
The players hated that Cassity might never be on the sidelines again.
"I really didn't think he'd coach anymore," Tiller said. "I thought he'd be bad off sick. But after he said he was fighting it and they caught it, I knew he was going to keep coaching."
And for that Tiller is grateful, even if Cassity is wearing red when UK faces Western Kentucky on Saturday night.
Cassity kept his eyes on his goal as poison tried to kill the cancer invading his body. He kept imagining what it would be like to wear that whistle again and run alongside his players when two-a-days started.
He got back in time for them. Sometimes he'd need to sit in the golf cart for a few minutes or take naps between sessions, but he had beaten cancer and gotten back to what he loved.
"He's tough, no doubt about that," Petrino said recently of Cassity. "You understand how precious life is and it is just great to have him around. He is a great football coach and a tremendous person."
Each day, Cassity's new players — his "18 defensive back sons" as he calls them — include him in their prayer at the end of practice.
"I wake up with a smile on my face every day and can't wait to get to work because I'm fortunate to have that opportunity," he said.
He remembers that each time he puts on his whistle.
Jennifer Smith: (859) 231-3241. Twitter: @jenheraldleader. Blog: ukfootball.bloginky.com.