Miller, a former first-round pick, and Harris, who went undrafted, spent the Super Bowl on the sideline with knee injuries, helpless to prevent the Broncos' blowout.
That was just the start of their arduous time together.
They were workout partners for six months in the offseason as they rehabbed from ACL surgeries, both of which were performed by Dr. James Andrews in Pensacola, Florida.
Since the start of the season, they've been the vanguard of Denver's defensive resurgence that has seen them rise to fourth overall and first in the NFL against the run.
They're two of the biggest reasons the Broncos are 6-1 heading into Sunday's showdown against the Patriots (6-2) in the 16th installment of Manning vs. Brady.
Miller, who had his right ACL repaired in January, has nine sacks, one shy of league leader Justin Houston. He's teamed with free agent DeMarcus Ware to give the Broncos the best pass-rushing partners in the NFL with 16 combined sacks and 45 tackles altogether.
Harris, who had his left ACL fixed in February, has 11 pass breakups, one shy of NFL leaders Vontae Davis and Perrish Cox. He's teamed with free agent Aqib Talib to give Denver the top cornerback tandem in the league, one that's collected five interceptions and broken up 21 throws.
Miller and Harris didn't just have their knees fixed earlier this year but they reshaped their bodies through organic weight loss and a determination to take some stress off their repaired ligaments.
''That helped me get faster,'' said Harris, who dropped a dozen pounds to 188. ''If I would have come back at the weight I used to be at, it would have been a lot harder on my knee.''
Same with Miller.
''You definitely shed some muscle mass and some extra weight just by going through the ACL process,'' said Miller, who's down 25 pounds to 245. ''I mean, I felt fast at 268, 270 pounds. I was fast, but I wasn't fast for a long time. I'd have one or two plays, I had the first three snaps of the drive. I feel like now I can do the whole drive.''
Harris said neither he nor Miller has hit his stride yet.
Miller has sacks in six straight games and Pro Football Focus says Miller has 34 sacks/hits/significant pressures on the quarterback over the last five games.
''I think as the season goes on, we're just going to keep getting better and better,'' Harris said. ''And our stamina is going to keep getting better and better. Because regardless of what anyone says, your knees get tired by the end of the game. And it's just something that we have to work through.''
Harris keeps saying he won't be 100 percent until the one-year anniversary of his surgery. It's not so much that he's in pain but still getting used to the new feel of his knee.
''Until it feels just like my right knee, then it's not all the way back, to me,'' Harris said.
Some of it's mental, too.
''You're worried, you think about it a lot, it doesn't feel the same,'' Harris said. ''So, it can mess with you mentally. But luckily on Sundays I'm good.''
For all their similarities, Miller and Harris have different motivations.
Miller wants to prove that last season, when he was limited to five sacks by a drug suspension and then his knee injury, was a fluke.
Harris wants to prove his monster 2013 season wasn't a fluke.
Like Miller, Harris isn't shy about stating that his goal is to become the best at his position. But while Miller is loath to compare himself to other pass rushers, Harris boldly proclaims his status as one of the game's top cornerbacks, one who wears his undrafted status as a badge of honor.
''That's where the chip on his shoulder came from,'' coach John Fox said. ''You do revel in that. He played well last year. I mean, losing him in the playoffs last year did not help us.''
Both Harris and Miller are making the case for hefty pay raises soon and they might very well be fighting each other for Comeback Player of the Year honors, too.
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