Wide receiver Cody Latimer opens a hallway door at Dove Valley and walks straight into the question that hung over him last season: Why couldn’t he get on the field?

As the Broncos’ second-round draft choice, he represented a prized rookie with breathtaking athletic ability. He jumped so high for passes during training camp, it appeared he might dunk the football off the defender’s helmet. Latimer exited the visiting team’s locker room at the Dallas Cowboys’ AT&T Stadium after the final preseason game smothered in optimism.

Then he was gone. A ghost in uniform. Two catches, 23 yards, 37 offensive plays in 16 regular-season games.

“It took me too long to actually catch on,” Latimer said. “I was in the playbook, but I could have done even more. When I actually got it, it was too late. It was just way different (than college). I would know the play, then Peyton (Manning) would change it. Then I’d get to thinking too much and play slower.”

Latimer was filled with doubt. He felt helpless for the first time on an athletic field. He fought frustration, but Latimer found help from teammates. The veteran receivers refused to let Latimer surrender. The former Indiana star looked like an all-pro on the scout team. They preached patience and believed in him, support he intends to repay this season.

“They kept me going when I was at practice getting yelled at with people saying I didn’t know what I was doing. They said repeatedly, ‘Your time will come,’ ” Latimer said. “They said I had it in me, that I have to go out there and show the world. Part of my grind is making them look good.”

Latimer began his climb to a possible starting job this season immediately after the Indianapolis Colts eliminated the Broncos in the playoffs. He returned to Fit-Speed in Weston, Fla., a sports training facility co-founded by New York Jets wide receiver Brandon Marshall. Latimer spent three months working out. No longer burdened by a predraft foot injury, Latimer added muscle — he now weighs a sculpted 215 pounds — and speed.

It showed at Manning’s Duke passing camp. The drills served two purposes.

“I got a lot of repetitions because there weren’t many guys there,” Latimer said. “And it kind of gave us a little head start on routes and different play calls in the new offense. I am faster than I was, shiftier.”

Emmanuel Sanders expressed confidence in Latimer last week. He predicted a breakout season for a young receiver whose ability to block — Latimer’s physical nature enticed the Broncos to draft him — should fit well in coach Gary Kubiak’s scheme.

“He’s a special player. He has strong hands, the physical tools,” Sanders said. “I think this is going to be the year he jumps onto the map.”

Kubiak’s relationship with Latimer dates back 13 months. Latimer visited the Baltimore Ravens leading up to the 2014 draft, meeting with Kubiak, then the Ravens’ offensive coordinator. He told Latimer their paths would cross again. Their intersection in Denver — sooner than either expected — brings lofty expectations.

“He showed a lot of flashes from me watching (film of) him in practice,” Kubiak said. “A lot of times being a rookie can be over- whelming. I think it’s time for him to make a big jump, not just a little jump. Obviously his playing time is fixing to pick up, and it needs to pick up. We need him.”

Latimer recognizes the opportunity. When he’s not at Broncos headquarters, he studies his playbook for at least two hours per night. He wants to leave nothing to chance.

“I am pounding it into my head. I have to make sure I get it especially by the time of minicamp,” Latimer said. “You don’t want to be out there looking like a fool.”

It’s easy to see Latimer as a typical young player trying to find his way. His story goes much deeper, providing evidence why last season’s adversity should not define him. His thoughts turn often to his family, those who love him and those he has lost. When Latimer was only 13, his father, Colby, died of cancer.

“Once you lose a parent, it really doesn’t get much harder than that,” Latimer said. “The funny part is that I grew up playing basketball, telling my dad I was going to the NBA. And he would say, ‘No, you are going to the NFL.’ I know he was smiling down when I got drafted. I know he’s proud of me.”

Cancer also claimed Latimer’s grandmother, and just this offseason an aunt he long had been close to. A decade of tragedy has changed Latimer. He recently launched a website — TheCodyLatimer.com — where T-shirts can be purchased with all proceeds earmarked for the American Cancer Society.

“I have learned how to deal with it. They are in a better place,” Latimer said. “It’s also why I want to give back, because I know they would love that.”

Latimer smiles as he heads down the Dove Valley hallway. Through the locker room door, where frustration once roiled inside him, he finds a fresh start. Support surrounds him. With each hour in the Broncos’ playbook, he vows to fulfill his promise.

“I have motivation,” Latimer said. “I am taking everything seriously. I am not going to let the coaches, my teammates, my family down. It’s a strong feeling. I don’t want to disappoint them.”

Troy E. Renck: trenck@denverpost.com or twitter.com/troyrenck