Sweeney visited the medical center in May, when he played for the Mariners.
"It really moved me," he said. "Some of these young men and women were in battle as recently as six, seven days before we visited. It really impacted my life. ... We're playing a game for a living. The way we play the game might give joy to a lot of people in our country, maybe even our soldiers. But the true heroes are those that defend our country."