Oh, Miller & Co. know what "Speedy" is all about, what flips his switch; put a football in Stewart's hands and he's instant energy.
He might be the mightiest competitor on CU's offense, no matter that he's smallish, soft-spoken and at times difficult to hear (and for Miller, that might be because Miller's ears seemingly rest about 31/2 feet higher than Stewart's mouth).
The Buffaloes' running game is largely dependent on the little guy. Until he returned against Wyoming last Saturday, still not fully recovered from a sore hamstring, CU had not produced a 100-yard rusher this season.
Stewart, though, carried a season-high 32 times for 127 yards and two touchdowns - a performance that might have looked even better on tape than it did in the warm sunshine radiating on Folsom Field.
"There were a couple of times when two or three people went unblocked and they couldn't tackle him - they weren't even getting close to him," CU running backs coach Darian Hagan said.
"He could put his foot in the ground and be horizontal or be at a 90-degree angle. It was ridiculous what he can do with his body. But the first guy is never going to tackle him . . . running back's got to make people miss, and he's a good example of that."
Added Miller, who stands 6-foot-8 to Stewart's 5-6: "He had a heckuva game, and that's wonderful to see as an offensive lineman, if you can open those holes. He was excited on the sidelines and after he got in and got his (first) touchdown, he just lit up. That's great to see, because that emotion spreads."
Stewart's and the Buffs' running game strides occurred despite an O-line shuffle that sent Miller from right guard to right tackle in place of Bryce Givens and had Keenan Stevens liberally subbing for starting center Mike Iltis, still bothered by a sore Achilles tendon.
In Miller's place at guard, Blake Behrens and Matt Bahr shared playing time, and line coach Denver Johnson said that rotation (and more) might continue for Thursday night's game at West Virginia (5:30 p.m. MDT, ESPN).
"We've got three guys now - Bahr, Behrens and (left guard) Ethan Adkins who are all pretty comparable," Johnson said. "We'll continue to rotate those guys . . . and Keenan certainly didn't hurt us when he was in there; he was an asset.
"The only way to develop depth is get guys in the game and have them continue to compete . . . the guys who play the best play the most."
Miller's inside-out switch went fairly well, according to the player and his coach. Johnson said Miller "did pretty well; there's lots of room for improvement, but he and I and all the others are committed to that.
"Ryan's always kind of considered himself a tackle. We talked about getting our best five players out there and going into the season that to get our best five out there, one of those tackles had to play guard.
"He was the obvious candidate . . . now with situation what it is at tackle, he was the obvious candidate to move back out there.
"I think he's got a comfort level there. I think in his heart, that's what he considers himself. You could tell he was a bit rusty and hadn't played out on the edge in a while.
"But you could also tell that he can certainly improve, and I expect great improvement before we play again. He's got a game under his belt and an open week as well. I would expect him to be much better."
Miller contended by Wednesday before the Wyoming game - only one full practice into his switch - he had rediscovered his comfort level.
During the game, he said, "There was maybe a little hesitation at first, but everything after the first quarter was fine . . . I was just trying to remember which plays are different for tackle and guard.
"I really don't think I need to settle in (at one position); we all have to be versatile. At first in fall camp I definitely had that mentality (of staying in one position). Now I think it's more of 'I'm an offensive lineman' and I'll play where I need to.
"If I need to play guard, I play it; if I need to play tackle, I play it. So, I think being able to be consistent at both positions is important."
It might be more important than he knows. O-linemen hop-scotching between positions remains a possibility, and with Givens' playing status murky (he has returned to practice after missing the Wyoming game for personal reasons), Johnson wants to begin allotting more work at tackle for redshirt freshman Ryan Dannewitz.
As simplification turned into last week's buzzword on defense, Hagan and Johnson said it wasn't uttered on offense.
"We didn't take anything out or add anything . . . same stuff," Hagan said. "But I think with how (Wyoming) played their front, we were able to get more double teams and not be worried about how many guys they had in the box. That was the only thing we did different."
But something else factored into CU's ground game success: The Buffs started fast and, for the first time this season, weren't forced to play from behind.
"We dictated the tempo, and it was our first time where we were able to concentrate on the run game," Hagan said. "We accomplished what we'd been trying to accomplish all year long, and that was getting our big guys on double-team blocks, fork-lifting guys up out of there. We were able to do that."
They're hoping for a recurrence against the Mountaineers, whose defensive front usually consists of three down linemen with three linebackers stacked behind them (a 3-3 stack).
It will be critical for CU's O-linemen to shed their blockers and get to the linebackers - a process Johnson compares to "sometimes like fighting bees in there."
Schematically, said Johnson, the Mountaineers "don't appear different. They've been running that defense for a good long while and are obviously ingrained in it and committed to it.
"There's always a wrinkle here or there, but it looks what they've been in for the last several years."
Added Miller: "We played an odd-structured team last week, so as far as game-planning, I'm not sure how much it's really going to change. That 3-3 with fast linebackers . . . I think we just need to get to the linebackers. If we can get off the down guys and get to the linebackers, I think we'll be OK."
In last season's game in Boulder, the Buffs efficiently coped with the 3-3 stack, gaining 366 yards in total offense (187 rushing, 179 passing) in their 17-14 overtime victory. And of the rushing total, Stewart ran for 166 yards on 28 carries.
Johnson and Miller contend the Buffs can flex their muscles with the Mountaineers - and all comers.
"Physically, I think we match up well with anyone," Miller said. We've got freaks - Nate (Solder) at left tackle, I'm at right and all of our interior guys are big.
"It's a relief to say that as an offensive line you've got a group of strong, physical guys."
Johnson "respects" West Virginia's defensive front, but adds, "Personnel-wise, it should be a competitive matchup. I would certainly think we'd be up to the challenge."