Miller is lining up at his strongside linebacker position during training camp but if the NFL denies his appeal and makes him sit out all of September for violating the league's substance-abuse policy, the Broncos have a range of options to fill the void.
There's Shaun Phillips, the 10-year veteran the Broncos signed during draft weekend as a potential replacement for Dumervil, who teamed with Miller to account for 29½ of Denver's league-leading 52 sacks last season. The Broncos also could move Nate Irving or Stewart Bradley from middle linebacker to Miller's spot, considered the fulcrum of a Jack Del Rio-coached defense, with Phillips replacing Robert Ayers on third down at right defensive end.
Or they could just send in Smith, the intriguing rookie from Western Kentucky.
The Broncos lost Dumervil this offseason when there was a mix-up with the fax machine that kept the team from receiving his signed contract in time. That made him a free agent, and he bolted to Baltimore.
After flirting with several other high-priced free agents, the Broncos settled on Phillips, a relative bargain at $1 million for one season, and Smith, whom they grabbed in the fifth round of the draft.
Smith was leading the nation with 12½ sacks last fall when he tore a ligament in his left knee that sent his spirits plummeting just two months after his monster game against Alabama had sent his draft stock soaring.
He missed most of the Broncos' offseason workouts but is fully recovered from his torn ACL and flashed his skills when training camp opened this week, displaying burst, brawn and, most significantly, an inside move that most rookies don't develop until they get beat down enough by tackles thwarting their outside speed rushes.
"I was impressed," coach John Fox said.
Smith first appeared on NFL radar screens last September when he sacked Crimson Tide quarterback AJ McCarron three times, beating an offensive line that included two first-round draft picks in D.J. Fluker and Chance Warmack and a fourth-rounder.
After tearing up his knee two months later, Smith couldn't attend the NFL combine or any of the all-star games, but those three sacks in Tuscaloosa were enough to show off his versatility and promise.
He displayed outside speed on the first one, blowing by Fluker on third-and-long. Then, he beat a double-team of Warmack and tackle Cyrus Kouandjio. Finally, he disengaged from Kouandjio to run down McCarron.
"If you want to be a good pass rusher you can't keep hitting the tackle with the same speed rush," Smith said. "He's going to kick out wide, so you've got to keep him off-balance, so that's why I go inside and it feels kind of natural to me going inside."
Smith of Loganville, Ga., said he didn't have the grades to go to an SEC school, and he didn't want to go the junior college route, so he went to Western Kentucky and his eyes got wide when he saw Alabama on the schedule last year.
"I always knew that I can play with whomever. I feel like I always had the talent," Smith said.
This trip to Bryant-Denny Stadium, though, that was his one shot to show everybody else pro scouts in particular that he could play with the big boys.
He sure did.
Then came Louisiana-Lafayette two months later and the play where he spun past the tackle, got pushed from behind and went down in pain.
Torn ACL. Season over.
"I mean, I was just hoping I was going to be drafted at that point," Smith said. "I was just hoping to get my chance."
The Broncos gave him that shot and circumstances being what they are, they won't have to wait around long to see if they made the right call.