"I'm not talking today, sorry," Marshall said in politely but firmly declining to speak to a reporter.
Marshall, who was reinstated Sunday after a nine-day suspension for conduct detrimental to the team, could be subject to a fine for failing to make himself available to reporters at least once during the week of practice leading up to Sunday's opener at Cincinnati.
Typically, though, the league first sends a letter to the offending player advising him of the NFL regulations mandating his minimum availability to the media. He could be fined if the behavior persists.
Coach Josh McDaniels imposed the suspension after Marshall's insubordinate antics during practice -- he swatted a pass away that he was supposed to catch and walked while the rest of the team ran -- became a distraction. But he said Friday he had no complaints since the return of Marshall, who has clashed with the organization off and on since the team rebuffed his overtures for a new contract.
"He's had a good week of practice," McDaniels said. "He's practiced hard. He's doing everything we're asking him to do."
The absence of drama to date in Marshall's return is being viewed as a positive sign by Shannon Sharpe, formerly a star tight end for the Broncos and a member of consecutive Super Bowl-winning teams in the late 1990s.
Sharpe said he reached out to Marshall by phone while the receiver served his suspension in hopes some candid advice from him would help Marshall get his act together.
During a three-way call that also included former Broncos receiver Rod Smith, Sharpe said he told Marshall flat out that he was wrong and urged him to start "acting like a grown man, a professional football player and conduct himself accordingly."
"You just can't condone behavior like that. Even if he was my brother, I'd still tell him he was wrong," Sharpe said.
Sharpe said Marshall seemed to take his words to heart and he said he believes Marshall has learned from what has been a painful lesson.
"I think he's handling this in a very positive way," Sharpe said. "Moving forward, I don't think the Broncos are going to have any problems with Brandon Marshall."
There may even be a reason behind his refusal to answer questions from reporters this week.
"I told him I think he should let his play do his talking," Sharpe said.