According to a Seahawks.com story from October of 2018, Glasgow was diagnosed with adenocarcinoma, which started in his stomach and liver.
"You never give up. Too many people give in to cancer and I'm telling you that it doesn't define you," Glasgow told the website. "I decided right away that I was not going to allow chemotherapy to dictate what happens next in my life. You fight, and you believe in yourself. I always have, and I always will."
Across his career, Glasgow began as a solid kick returner his rookie year, tallying 352 yards on punt returns and 1,126 on kick returns in 1979. His return days lessened as his impact in the defensive backfield grew. He was a mainstay as a starting free safety and then strong from 1980 to 1987 with the Colts. After moving on to the Seahawks, he started 29 games over the 1989-1990 seasons.
Glasgow had 15 interceptions and 17 fumble recoveries in his career.
Though he was a veteran of more than a decade in the NFL, Glasgow is likely most revered for his days at the University of Washington. As a Husky, he was a multiple time All-Pacific 8 selection as a cornerback and most famously garnered a game-sealing interception in the end zone during the 1978 Rose Bowl, which Washington won, 27-20, against Michigan. Now, Glasgow lives on as an inductee in the Husky Hall of Fame, where he was enshrined in 2001.