Now, he's fighting just to make the roster.
Ball started camp as Anderson's backup but slipped behind Ronnie Hillman, who's averaged 7.4 yards a carry this preseason, and Juwan Thompson, who also shines on special teams, something Ball doesn't do.
Ball has carried the ball just 16 times in the preseason and is averaging a paltry 2.6 yards a carry heading into the exhibition finale Thursday night against Arizona.
''It is tough because I feel like I really haven't had the opportunities in these preseason games, but there's still one more left and I feel like I'll have some playing time in this one, and I'll show them what I can do,'' Ball said.
If Ball makes the team as the fourth running back, he could be facing deactivation on game days. But there's no guarantee he'll survive the 53-man cut because the Broncos might have to use that roster spot somewhere else.
Ball, who sent an NCAA record with 83 touchdowns at Wisconsin, acknowledged he was stunned Saturday night when he watched three running backs get into the game ahead of him. He finished with just 11 yards on four carries against San Francisco.
''I was expecting a lot more playing time,'' Ball said. ''It caught me off-guard, but my head's not down. I'm going to keep it up and keep fighting.''
The Broncos' clear-cut starter a year ago at this time after rushing for a 4.7-yard average his rookie year, Ball never regained his explosiveness or his starting job after undergoing an emergency appendectomy in August. He blamed the three-week layoff for weakening his core, which he said in turn led to the torn right groin that landed him on injured reserve.
He finished with only 172 yards on 55 carries for a 3.1-yard average and a single TD in 2014. As a rookie backup, he rushed for 559 yards on 120 carries for a 4.7-yard average and four touchdowns.
Coach Gary Kubiak said Ball and Kapri Bibbs ''will get the bulk of the work'' Thursday night. ''They both deserve plenty of touches and they will get them. And they will both play special teams, too. We've talked about the Montee deal. He needs a bunch of carries and he'll get them.''
Kubiak said he wants to see Osweiler ''solidify what he's done in the preseason in a lot of ways. He's played well. I think he has improved a great deal from OTAs through training camp. He knows the team is his.''
At least when Peyton Manning's taking a breather, which happened a lot this summer.
''He's got a bunch of young guys that are playing with him. From a quarterback standpoint, your play should reflect through those young guys,'' Kubiak said. ''You should raise their level of play. So, that's what I want to see him do.''
Siemian has also played well this summer, so much so it's unlikely the Broncos will be able to slip him through to the practice squad.
''It's out of my control, so it's tough for me to worry about those kinds of things,'' the rookie seventh-round pick from Northwestern said. ''I've had fun going out and playing when I have, so I'm just thankful to get a chance.''
Notes: The Broncos released WR Nathan Palmer, TE Dan Light and LB Danny Mason to reach the 75-player limit. ... Kubiak said one possible exception to his plan to sit the starters is DE Derek Wolfe, who will begin serving a four-game drug suspension Sunday. ... Kubiak said he plans to put new LG Evan Mathis in pads Wednesday and again before Thursday night's game. ''So, he'll get two good workouts in,'' Kubiak said.
AP NFL website: www.pro32.ap.org and www.twitter.com/AP-NFL
Follow AP Pro Football Writer Arnie Melendrez Stapleton on Twitter: http://twitter.com/arniestapleton