ENGLEWOOD, Colo. -- When training camp began, the Denver Broncos expected a competition to percolate at strong safety between Mike Adams and David Bruton.
Adams, the incumbent, had an average season as the starter last year.
Bruton, a backup since 2009, saw first-team repetitions during minicamp and organized team activities, and 2011 starter Quinton Carter was expected back to full health after undergoing microfracture knee surgery last September.
In Thursday night's preseason opener at San Francisco, a name finally rose to the top.
After his performance in that game, Ihenacho lined up with the starters in practice Saturday.
Ihenacho, a previously unheralded second-year player who went undrafted, spent most of his rookie season on Denver's practice squad and was expected to compete for one of the final spots on the roster, or eventually return to the practice squad. But his emergence has been the biggest surprise of training camp, and after two weeks of being the most aggressive, energetic player on the field, he backed that up with seven tackles, a forced fumble and aggressive play against the run.
Ihenacho played like he practiced, and two days later, when the Broncos returned to training-camp work, he remained on the first team alongside Rahim Moore.
"I told him to go out there and just do him and he did exactly what he does in practice," said Moore. "He flew around. He made tackles, made plays and every time you see him he's always flying in the play. He's come into his own."
And not a moment too soon. The expected charge from Carter has yet to materialize because his recovery has gone slower than expected. He didn't play against San Francisco and hasn't practiced in 10 days. Bruton is the biggest and fastest of the Broncos safeties, but hasn't fared as well in full-contact, full-speed work as he did in the offseason. Adams can still provide depth, but is a more natural fit at free safety, which Moore did well until his late-game misplay in the divisional round of the playoffs last January.
Into that breach stepped Ihenacho, who returned two interceptions for touchdowns during the first four days of training camp and quickly established himself as an effective run defender. That came to the forefront early against San Francisco, when he charged forward, filled a gaping hole and tackled 49ers running back LaMichael James, limiting him to a 5-yard gain and preventing a potential run of 20 yards or more.
A play like that came as no shock to the senior member of the secondary and longest-tenured Bronco, cornerback Champ Bailey.
"I see him do it every day in practice, so it's not a surprise to me," Bailey said. "I know it's going to be a surprise to a lot of people; he hasn't played a lot in this league. But he's coming on. He's a guy that's grown a lot, and he knows how to play the safety position, and I look forward to seeing him play all year."
All year. Not just for a cameo. The depth chart the team issued in its press release Saturday still listed Adams on the first team, but after one game, it's clear the spot is now Ihenacho's to lose.
--Team correspondents for The Sports Xchange contributed material for this story.