DENVER (Reuters) - Denver Broncos wide receiver Kenny McKinley, who was found dead in his home this week, had been depressed and told friends "he should just kill himself," investigators said.

McKinley, 23, died on Monday of a gunshot wound in an apparent suicide, Arapahoe County (Colorado) officials said.

"He had made statements while playing dominoes shortly after (knee) surgery that he should just kill himself," said an investigator's report issued by the Arapahoe County (Colorado) Sheriff's Office late on Tuesday.

"No one believed he was serious," added the report.

McKinley had undergone season-ending knee surgery last month and that had left him depressed, the report said.

"He had made statements that he didn't know what he would do if he could not play football and that football was all he knew," the sheriff's report said.

The second-year player was found dead in the master bedroom of his Denver-area home.

Arapahoe County's corner said the death appeared related to a self-inflicted gunshot wound.

He is survived by his parents and a one-year-old son.

A tearful Broncos coach Josh McDaniels remembered McKinley as "a special person (who) had a great smile, a great personality, always in a good mood, certainly well-liked by everyone who knew him," the Denver Post reported (www.denverpost.com).

The team will hold a moment of silence before Sunday's home game with the Indianapolis Colts, and players will wear a decal with McKinley's number 11, the Broncos said on their website (www.denverbroncos.com)

The Broncos also decided to leave McKinley's locker untouched for the remainder of the season.

"We've got to play with him on our shoulders and in our hearts," linebacker Wesley Woodyard said. "I think that's something that's going to allow us to continue push through this week."

A fifth-round draft choice in 2009, McKinley was the third Broncos player to die in four years.

Cornerback Darrent Williams, 24, was killed in a drive-by shooting in Denver in January 2007.

The same year running back Damien Nash, also 24, died of heart failure after a charity basketball game in St. Louis.

(Reporting by Gene Cherry in Raleigh, North Carolina; Editing by Steve Ginsburg)