(CBSNEWS) – Arizona Cardinals wide receiver Larry Fitzgerald has written a moving tribute to his friend, Sen. John McCain, who is battling an aggressive form of brain cancer.

“We’ve become friends since I’ve been playing for the Cardinals,” Fitgerald writes for Sports Illustrated’s website. “I have so much admiration for him, and I wanted to share why that admiration has become so strong.”

Fitzgerald, widely considered a shoo-in for the NFL Hall of Fame after he retires, insists that he’s “not much of a political guy.” However, he admires McCain for serving his country during the Vietnam War and how he “votes his conscience.”

“The sacrifices John McCain has made for our country, and especially the men and women he served with in the military, are incredible,” Fitgerald writes of the Arizona Republican. “As a prisoner of war in Vietnam he missed six Christmases with his family back home and suffered unbelievable hardship. Yet most people don’t realize that he could have gotten out of that prisoner of war camp four years earlier than he did because his father was a high-ranking military commander.

However, he refused to be freed until all the men captured before him were released. That is true heroism and bravery. He gave so much in the service of his country, and that commitment to service continued as he was elected to Congress in the 1980s.”

Fitzgerald, who has played for Arizona his entire professional career, notes that McCain is an “avid Cardinals fan” and that their “relationship has grown throughout my career.” Fitzgerald also recounts that, during a trip to Vietnam, he toured the lake where McCain was shot down and captured by North Vietnamese soldiers.

“When Senator McCain was hit, the plane went into a spin and was going to crash,” Fitzgerald writes. “He bailed out, and went crashing into Truc Bach Lake just outside of Hanoi. His left arm was broken. His right arm was broken in three places. His right leg was broken. He was in such pain when he fell into the lake that he almost drowned. He had to inflate his life vest with his teeth because he couldn’t use his arms.”