updated 6:23 p.m. ET March 27, 2008

ENGLEWOOD, Colo. - Immature? Sure. Bad guy? No way.

Denver Broncos star wide receiver Brandon Marshall, who keeps finding his name in negative news reports, insisted Thursday he’s really a good guy who just needs to grow up.

“Being truthful, it is time for me to grow up on and off the field,” Marshall said Thursday. “I’m not just a guy that’s on the team, I’m a starter and have a lot of responsibility on this team. We have goals that we’re trying to reach, and I play a big role in that.”

It was Marshall’s first extensive public comments since his latest misstep, a freak accident that landed him in the operating room for surgery on his right arm and called into question his maturity level again.

“It’s time for me to grow up,” he added. “From here on out, it’s Brandon Marshall, clean-cut guy. Just trying to get my life together as far as accidents and DUIs.”

Marshall said he was horsing around with his older brother, Fred, at a resort in Orlando, Fla., on Saturday when he tried to avoid a McDonald’s fast-food bag and fell into a television set, cutting an artery, a vein, a nerve, two tendons and three muscles in his right arm. He’s expected to need four months of recovery, a timeline that would make him available for the start of training camp in late July.

Marshall said he understands the public might be suspicious of his explanation, figuring instead that he got hurt in a street fight or in a barroom altercation. But he swore it was just a freak accident that happened while his family was preparing to go jet-skiing.

“It was just ’horseplaying,’ what brothers do,” Marshall said. “We’re adults, I just turned 24 Sunday. He’s 25. He’s my brother. I love him to death. We were just playing around like usual. We always play around. Maybe it will be in my next contract not to horseplay. He lives with me in Denver. He will continue to put deodorant to my under arm until my arm gets better.”

At first, Marshall downplayed the seriousness of the injury, but news of its actual nature came out Monday, the same day a jury trial was postponed for Marshall, who is accused of driving under the influence in downtown Denver following a game against Pittsburgh last October. A new trial date was set for June.

“There’s been things that I’ve been involved with as far as DUI. Stupid. It’s stupid. But it’s one of those things that I have take that and better myself. Learn from it. It’s stupid,” Marshall said. “I shouldn’t have been driving. I could have hurt someone that night. I could have hurt myself. I have to be accountable for my actions.”

Marshall also had a spat with his girlfriend last year that landed him in court and was partying with Darrent Williams the night the cornerback was slain in a drive-by shooting on Jan. 1, 2006. Former teammate Javon Walker said Marshall sprayed champagne on some bar patrons, sparking a confrontation that preceded the shooting, which remains unsolved.

In his impromptu meeting with reporters on Thursday, Marshall made light of a newspaper columnist who called him immature, but he agreed that he needs to act his age.

“I have a lot of growing up to do,” Marshall said. “I should never have gotten a DUI. You should never hear negative stuff about Brandon Marshall in the media. I know right from wrong. And I’m a great person with a big heart. But it is time, on a serious note, to grow up.

“My goal for this summer is to be clean-cut and don’t get into trouble ... and just hang around the right people.”

Marshall, a fourth-round draft choice in 2006 out of Central Florida, blossomed into the Broncos’ best receiver last year, catching 102 passes for 1,325 yards and seven touchdowns. His emergence as Jay Cutler’s primary target facilitated the recent release of Walker, who signed with Oakland.

Marshall missed most of training camp last year while nursing a pulled quadriceps muscle before coach Mike Shanahan nudged him back onto the practice field.

Marshall said Shanahan “was very understanding” about his latest injury, saying the coach “understood it was an accident.”

“I’m a good person. We can put a blog up and for everyone I came in contact with, from the bank to the movie theater, anywhere in the community, there’s going to be a lot of good things said about me,” Marshall said. “There’s times, I might (have) a little road rage or something, but I’m human. No one’s perfect. But I guarantee the good outweighs the bad.”

Marshall said he has no doubts he’ll be healthy in time for training camp and that he’ll have another outstanding season in 2008.

“This is just a minor setback,” he said. “But nothing good comes easy. There’s better days to come.”

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