University of Colorado Athletics
Mack’s Backfield Comes In Every Shape
August 21, 2026 | Football
BOULDER — Johnnie Mack doesn't have a type.
Colorado's running backs coach looks around his room and sees 205-pound downhill runners, 165-pound sprinters, a 215-pound bowling ball who can do both, and — in Brennan Marion's Go-Go offense — a scheme that has a job for every one of them.
"With our running game, we pretty much run everything," Mack said Thursday. "We got big guys, like the Damian Hendersons and the Richard Youngs, and then we got the speedsters, and the power guys like Micah Welch — he could be both. And we got DeKalon Taylor, that can make guys miss on the third level, as well as JaQuail Smith, that can do a multitude of things as well. So it's always good in the Go-Go offense, especially with the multitude of formations and different styles of plays that we do."
Before any of it, Mack starts with the number of bodies.
"That's always good at the running back position," he said. "We all know that playing that position is very physical, and sometimes it's hard to make it through a season. So to have some depth this year within the room, it builds competition, and it just makes you feel a little better when you know you got depth."
The room's anchor is experience. Third-year back Micah Welch is entering his third season, all at the Power Four level, and Mack challenged him this offseason to let that show.
"His work ethic from this offseason to now — Micah put in a lot of work this year," Mack said. "There's times that we had breaks to go home. He didn't go home. He stayed around. He worked out. The kid loves football, man. He don't have a plan B. This is it for him. So he's putting in a lot of work, and as you see, he's running with an attitude. He's running with a purpose."
Around Welch, Mack restocked with production, headlined by the two transfers who followed Marion's offense from Sacramento State — Damian Henderson II and second-year back JaQuail Smith. Smith arrived already fluent in the scheme, and with a simple scouting report on himself.
"Speed," Smith said. "I try to make a lot of people miss. I don't try to let the first guy bring me down. I just like scoring touchdowns."
He also arrived believing the offense hasn't shown anything yet.
"It's going to expand the Go-Go," Smith said. "The Go-Go is not going to be like how the Go-Go was last year and the year before that. It's really going to expand this year, so it's going to be fun to watch."
Playing running back in this system means more than carrying it, Smith said, and that's the point.
"You got to be a running back to be able to do everything," he said. "So you got to be like a third-down back — be able to block, run, catch out the backfield."
The backfield even borrows from other rooms. Fifth-year tight end Brady Kopetz has been taking snaps at fullback, and the 270-pounder — a high school tailback for nine years before he ever played tight end — sounds like a man who found his way home.
"I always love hitting someone with a running start," Kopetz said. "Being in the backfield reminds me of high school. Being able to get in a three-point stance in the backfield and really have a physical play and make an impact like that — nothing fires me up more."
Where all that tonnage matters most is the part of the field that has frustrated this program for years. Mack has made short yardage a daily point of emphasis.
"Once you get in that red zone, that goal line, it's really all a mentality right there, man," Mack said. "When we get that close, we got to put it in. I mean, three points, we're happy about, but we rather take the six. We rather take the six. So your mindset got to really change when you get in there."
Mack was an assistant smiling to himself when Marion got the coordinator job, because he knew what the system meant for his guys. Two weeks out from the Sept. 3 opener at Georgia Tech, he wants them treating it that way.
"I knew his offense was built for running backs to have success," Mack said. "To me, you don't need any more motivation, right? If I got to give you any more motivation about that, then you may be on the wrong team. Now we just got to continue to put in the work and make sure, man, that we apply pressure."
Colorado's running backs coach looks around his room and sees 205-pound downhill runners, 165-pound sprinters, a 215-pound bowling ball who can do both, and — in Brennan Marion's Go-Go offense — a scheme that has a job for every one of them.
"With our running game, we pretty much run everything," Mack said Thursday. "We got big guys, like the Damian Hendersons and the Richard Youngs, and then we got the speedsters, and the power guys like Micah Welch — he could be both. And we got DeKalon Taylor, that can make guys miss on the third level, as well as JaQuail Smith, that can do a multitude of things as well. So it's always good in the Go-Go offense, especially with the multitude of formations and different styles of plays that we do."
Before any of it, Mack starts with the number of bodies.
"That's always good at the running back position," he said. "We all know that playing that position is very physical, and sometimes it's hard to make it through a season. So to have some depth this year within the room, it builds competition, and it just makes you feel a little better when you know you got depth."
The room's anchor is experience. Third-year back Micah Welch is entering his third season, all at the Power Four level, and Mack challenged him this offseason to let that show.
"His work ethic from this offseason to now — Micah put in a lot of work this year," Mack said. "There's times that we had breaks to go home. He didn't go home. He stayed around. He worked out. The kid loves football, man. He don't have a plan B. This is it for him. So he's putting in a lot of work, and as you see, he's running with an attitude. He's running with a purpose."
Around Welch, Mack restocked with production, headlined by the two transfers who followed Marion's offense from Sacramento State — Damian Henderson II and second-year back JaQuail Smith. Smith arrived already fluent in the scheme, and with a simple scouting report on himself.
"Speed," Smith said. "I try to make a lot of people miss. I don't try to let the first guy bring me down. I just like scoring touchdowns."
He also arrived believing the offense hasn't shown anything yet.
"It's going to expand the Go-Go," Smith said. "The Go-Go is not going to be like how the Go-Go was last year and the year before that. It's really going to expand this year, so it's going to be fun to watch."
Playing running back in this system means more than carrying it, Smith said, and that's the point.
"You got to be a running back to be able to do everything," he said. "So you got to be like a third-down back — be able to block, run, catch out the backfield."
The backfield even borrows from other rooms. Fifth-year tight end Brady Kopetz has been taking snaps at fullback, and the 270-pounder — a high school tailback for nine years before he ever played tight end — sounds like a man who found his way home.
"I always love hitting someone with a running start," Kopetz said. "Being in the backfield reminds me of high school. Being able to get in a three-point stance in the backfield and really have a physical play and make an impact like that — nothing fires me up more."
Where all that tonnage matters most is the part of the field that has frustrated this program for years. Mack has made short yardage a daily point of emphasis.
"Once you get in that red zone, that goal line, it's really all a mentality right there, man," Mack said. "When we get that close, we got to put it in. I mean, three points, we're happy about, but we rather take the six. We rather take the six. So your mindset got to really change when you get in there."
Mack was an assistant smiling to himself when Marion got the coordinator job, because he knew what the system meant for his guys. Two weeks out from the Sept. 3 opener at Georgia Tech, he wants them treating it that way.
"I knew his offense was built for running backs to have success," Mack said. "To me, you don't need any more motivation, right? If I got to give you any more motivation about that, then you may be on the wrong team. Now we just got to continue to put in the work and make sure, man, that we apply pressure."
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