Ronnie Hillman became a ghost in uniform. He spiraled from the top of the depth chart to a Sunday inactive. He entered this year’s organized team activities (OTAs) guaranteed reps — and little else.

He needs to make the team. It starts by making the Broncos forget last season, an opportunity that slipped through Hillman’s fingers.

“I have a chip on my shoulder now,” Hillman said. “I am not paying too much attention to the depth chart. But I am not out here practicing to be No. 2.”

Hillman represents an interesting player on a team whose vacancies are scant. As great teams go, the Broncos possess real questions at middle linebacker and running back. Denver refused the temptation to add a veteran insurance policy, aside from Nationwide, passing on Ronnie Brown, Michael Bush and Felix Jones. That decision reflects the Broncos’ confidence in Montee Ball and the crew behind him: Hillman, C.J. Anderson, Brennan Clay and CSU’s Kapri Bibbs.

Hillman faces a challenge. The only thing harder than winning a starting job is regaining it. It starts with his hands. Hillman held the green football Monday, a practice that began last week with Peyton Manning and Demaryius Thomas. The prop reminds players of the importance of ball security.

The Broncos fumbled 19 times last season, counting the playoffs, worst in the NFL. Hillman fumbled twice, both times inside the opponents’ 10-yard line, after fumbling twice in the preseason. When the ball hit the ground in Indianapolis, the Broncos ran out of patience. His next rushing attempt came two months later.

“The green ball means something. You have to be accountable,” Hillman said. “I am going about it more like it’s a business. I am studying more and making sure when I am called on that I am ready to go.”

Dismissing Hillman is easy. And it would be a mistake. He’s only 22. By age, this should be his first season in the NFL. He was playing up in a league that eats its young.

Hillman weighs 205 pounds and says he hasn’t lost his burst with added strength. He can be a change-of-pace back. He must change his place on the depth chart, which starts by holding onto the green football with white knuckles.

“I know I can be better. I am barely touching the ceiling of what I can do,” Hillman said. “These next couple of months, I am going to prove it.”

Walk the line. Monday, the Broncos continued moving bodies up front with Winston Justice receiving a look at right tackle and Vinston Painter taking some reps at guard. Chris Clark entered OTAs first at right tackle, but Denver wants to keep an open mind along the line.

“Right tackle is the offensive center position of a year ago,” coach John Fox said. “We like our options. They will all get opportunities, and we will see what our best configuration is.”

Footnotes. Kicker Matt Prater remains absent from OTAs with an undisclosed illness but, Fox said, “he’s going to be fine.” … Fox bristled when it was suggested that backup quarterback Brock Osweiler struggled Monday. “I will let you make that evaluation. I believe he’s making progress.”

Troy E. Renck: trenck@denver-post.com or twitter.com/ troyrenck