Until Monday, Brandon O'Brien was chasing a dream.

The 30-year-old, once a walk-on at Kentucky who went on to serve a four-year term in the Marines, just finished a stellar career as a wide receiver at Montana State Northern University. For the past few months he was training at Athletes Performance Institute in Texas, hoping an NFL team would take a chance on him.

But that all changed Monday.

After two bombs exploded near the finish line of the Boston Marathon, killing three people and wounding dozens more, O'Brien has decided to re-enlist in the Marines.

"He said watching what happened yesterday left him with a big hole in his heart and told me he wants to ensure that this never happens again to anybody, anywhere," O'Brien's agent, Brad Berkowitz, told NFL.com. "The kid is a real hero."

It would have admittedly been a long shot for O'Brien to catch on with a team, but he has posted some solid times -- a 4.56 second 40-yard dash and a 4.08 second short shuttle. He participated in the NFL's Regional Combine in Houston on Feb. 16 and in his school's Pro Day on March 18.

O'Brien never gained much acclaim because he starred at a small school, but Roy Holmes, O'Brien's trainer at Athletes Performance Institute, had high hopes.

"If someone brings him into camp, I think they might be very pleasantly surprised," Holmes said.

O'Brien's story vaguely resembles that of Pat Tillman, the stellar defensive back who, inspired by the events of Sept. 11, 2001, turned down the NFL and enlisted in the army. Although their circumstances are different, it's impossible to deny that both men are true heros.

UPDATE: In an interview with Beyond Sports Network, O'Brien said he has not yet decided to re-enlist in the Marines. He is still considering enlisting in the armed forces, but he said his decision was not related to the Boston Marathon bombings.

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