Former Boise State quarterback Kellen Moore left Detroit five weeks ago feeling comfortable in the Lions’ offense.

He returns Sunday hoping to prove he’s worthy of a roster spot.

Lions rookies begin training camp Monday and veterans report Thursday. Moore is the Lions’ No. 3 quarterback, but team leaders say they might only keep two quarterbacks if they believe they can get more value out of a player at another position.

“The bottom line is just executing in preseason,” Moore said. “That’s the name of the game for the quarterback. Move the team down the field and manage the offense and score some points.”

Moore, an undrafted free agent after setting an NCAA record with 50 career victories for Boise State, is one of a record 25 former Broncos headed to training camp with 18 different NFL teams. The Arizona Cardinals begin training camp Monday, with the rest of the teams scheduled to hit the practice field by the end of the week.

Preseason games begin Aug. 5.

Moore should get plenty of preseason action because the Lions already know what they have with starter Matthew Stafford and veteran backup Shaun Hill. Moore and former Arena Football League quarterback R.J. Archer are the wild cards.

“(Moore) has grasped the offense very well,” Lions coach Jim Schwartz told MLive.com during practices in June. “He has command when he’s out on the field. He finds a way to get it done. He’s a guy, it’s well documented, doesn’t have the strongest arm, doesn’t have the prototypical size, but once you get out on the field, you don’t get any extra points for being 6-foot-4.

“You get seven points for moving the ball and getting it in the end zone, and that’s what he has done so far in training camp. He’s really smart, doesn’t get rattled, and takes good command of the huddle. He’s been impressive so far. Again, the real evaluation will start coming when you get to the preseason games, particularly with quarterbacks.”

Moore spent about six weeks with the Lions for a string of camps, beginning with the rookie mini-camp. The biggest challenge, he said, was learning the language of Detroit’s offense. It’s a one-back attack that is flexible enough to take advantage of the team’s variety of explosive offensive weapons.

“It’s all the same concepts (as Boise State),” Moore said. “Football is kind of the same deal. It’s connecting the dots and getting comfortable with all the verbiage.”

He enjoyed his time with the Lions’ coaches — including offensive coordinator Scott Linehan, uncle of Boise State tight end Gabe Linehan — and was welcomed warmly by Stafford and Hill, he said.

“Like everything, you kind of get more comfortable as it goes,” Moore said. “Leaving, I felt very comfortable — reaching that point where you have a very good grasp of the offense and you’re able to start playing.”

He could make his NFL debut in 19 days — a home preseason game against the Cleveland Browns on Aug. 10 — and finally begin to answer one of the most popular questions in football the past two years: Will Moore, at 6-foot, 197 pounds, survive in the NFL?

Moore believes he will.

“I’m excited for it,” he said, “and we’ll just see what happens.”

Here’s a look at the former Broncos on NFL rosters:

DOLPHINS

Who: WR Legedu Naanee (No. 19, sixth year), DE Jarrell Root (No. 70, rookie)

Camp opens: Thursday

Preseason opener: Aug. 10 vs. Tampa Bay

The skinny: Naanee signed with the Dolphins after a breakout season with the Panthers (44 catches, 467 yards). He joins a team in need of help at the position. Root signed as an undrafted free agent.

JETS

Who: CB Kyle Wilson (No. 20, third year)

Camp opens: Thursday

Preseason opener: Aug. 10 at Cincinnati

The skinny: Wilson has been often criticized through his first two seasons in the NFL, but the former first-round pick was better last year. He is expected to be the No. 3 cornerback and play about half the snaps this year.

BENGALS

Who: S George Iloka (No. 43, rookie)

Camp opens: Thursday

Preseason opener: Aug. 10 vs. New York Jets

The skinny: The Bengals are shorthanded at safety, so there’s an opportunity available for Iloka to play his way onto the field.

BROWNS

Who: DL Billy Winn (No. 79, rookie)

Camp opens: Thursday

Preseason opener: Aug. 10 at Lions

The skinny: The Plain Dealer of Cleveland reports that the Browns considered Winn “a huge steal” in the sixth round of the draft. He will be given a chance to compete for the job vacated by injured tackle Phil Taylor, who is out for the first half of the season at least.

BRONCOS

Who: OT Ryan Clady (No. 78, fifth year)

Camp opens: Wednesday

Preseason opener: Aug. 9 at Chicago

The skinny: Negotiations between the former first-round pick and the Broncos on a contract extension have not gone well, according to The Denver Post. This is the final year of Clady’s contract. He is one of just five offensive linemen in NFL history to start every game and make two Pro Bowls in his first four seasons.

RAIDERS

Who: TE Kyle Efaw (No. 81, rookie)

Camp opens: July 29

Preseason opener: Aug. 13 vs. Dallas

The skinny: The Raiders are looking for a couple of playmakers to emerge at tight end. Efaw was added as an undrafted free agent.

COWBOYS

Who: DE Tyrone Crawford (No. 70, rookie), CB Orlando Scandrick (No. 32, fifth year)

Camp opens: July 29

Preseason opener: Aug. 13 at Oakland

The skinny: The Cowboys overhauled their cornerback crew during the offseason but seem committed to Scandrick. They signed him to a five-year contract last year. Still, he isn’t expected to start with newcomer Brandon Carr and first-round pick Morris Claiborne on the roster. The Cowboys hope Crawford can provide a pass-rush boost immediately and develop into a full-time player.

REDSKINS

Who: CB Brandyn Thompson (No. 32, second year)

Camp opens: Wednesday

Preseason opener: Aug. 9 at Buffalo

The skinny: Thompson spent last year bouncing between the practice squad and active roster. He likely is on the roster bubble in training camp, too.

BEARS

Who: DE Shea McClellin (No. 99, rookie)

Camp opens: Wednesday

Preseason opener: Aug. 9 vs. Denver

The skinny: The Bears are counting on McClellin to provide a second fearsome pass rusher to go with Julius Peppers (100 career sacks). McClellin likely will be the third end, spelling the two starters and teaming with Peppers in passing situations. McClellin is in a somewhat awkward spot — there are doubts about the Bears’ decision to draft him at No. 19 overall, and his performance will be used by the media to evaluate first-year General Manager Phil Emery.

LIONS

Who: QB Kellen Moore (No. 17, rookie), WR Titus Young (No. 16, second year)

Camp opens: Thursday

Preseason opener: Aug. 10 vs. Cleveland

The skinny: Young hopes to expand his role to return specialist this season. More importantly, he needs to avoid the coaches’ doghouse — he already has been there at least twice in his short career for letting his emotions get the better of him. Young was a dynamic kickoff returner at Boise State but didn’t get many chances on punts. “Our coach (Chris Petersen) had like a no tolerance for not catching the ball, or not really fielding the ball, so I didn’t really do as well, get too many opportunities” on punt returns, Young told the Detroit Free Press. “But punt return is really where my heart is. Ever since I was younger, that’s where I really got noticed at. Just catching the ball and just making a lot of people miss.”

VIKINGS

Who: DL Chase Baker (No. 62, rookie), CB Chris Carr (No. 25, eighth year)

Camp opens: Thursday

Preseason opener: Aug. 10 at San Francisco

The skinny: The Vikings boast one of the best defensive lines in the NFL, so Baker will be challenged to make the roster. Carr, who signed a one-year contract after he was released by the Ravens, will compete for the second or third cornerback spot. “It’s like you have to reprove yourself all over again,” Carr told the St. Paul (Minn.) Pioneer Press. “It feels pretty good now that I have that chance.”

FALCONS

Who: TE Tommy Gallarda (No. 87, first year)

Camp opens: Wednesday

Preseason opener: Aug. 9 vs. Baltimore

The skinny: Gallarda could fit the team’s need for a blocking tight end. He was on the practice squad for part of last season.

PANTHERS

Who: TE Richie Brockel (No. 47, second year)

Camp opens: Friday

Preseason opener: Aug. 11 vs. Houston

The skinny: Brockel likely will face some competition in camp, but he carved out a nice niche as a fullback/tight end hybrid last season.

SAINTS

Who: FB Korey Hall (No. 35, sixth year); LB Aaron Tevis (No. 48, rookie)

Camp opens: Tuesday

Preseason opener: Aug. 5 vs. Arizona (Canton, Ohio)

The skinny: Hall primarily played on special teams in his first season with the Saints. Tevis signed as an undrafted free agent.

BUCCANEERS

Who: RB Doug Martin (No. 22, rookie)

Camp opens: Thursday

Preseason opener: Aug. 10 at Miami

The skinny: Martin, a first-round pick, is expected to team with LeGarrette Blount to form a potent 1-2 punch in the running game for the Bucs. They liked Martin in part because of his ability to play in passing situations as a blocker and receiver, which is a weakness for Blount. There’s even some speculation that Martin will win the starting job. “The things that we liked when we drafted him were his quickness, his balance and his vision,” coach Greg Schiano said, according to The Ledger. “I hope, what we saw on his college tape, he can bring that to the National Football League. There’s no reason to believe he can’t.”

CARDINALS

Who: OG Daryn Colledge (No. 71, seventh year), OT Nate Potter (No. 76, rookie)

Camp opens: Monday

Preseason opener: Aug. 5 vs. New Orleans (Canton, Ohio)

The skinny: Colledge and Potter are an interesting pairing, because they are two of Boise State’s most decorated linemen and they developed a friendship training together in the offseasons. Colledge is a fixture at guard, having signed a big free-agent deal last summer, but Potter is a seventh-round pick who will be fighting to make the team.

RAMS

Who: WR Austin Pettis (No. 18, second year), S Quintin Mikell (No. 27, 10th year)

Camp opens: Saturday

Preseason opener: Aug. 12 at Indianapolis

The skinny: Pettis is in a difficult spot. He must sit out the first two games to complete his four-game suspension from last season for testing positive for performance-enhancing drugs — and he’s playing for a new coach. He likely will need to impress in camp to hold on to his spot. Mikell was the team’s second-leading tackler last season and should be a staple again this year.

SEAHAWKS

Who: S Jeron Johnson (No. 32, second year)

Camp opens: Friday

Preseason opener: Aug. 11 vs. Tennessee

The skinny: Johnson played in eight games last season as an undrafted free agent, largely on special teams, but could earn more playing time this year with a strong camp.

Chadd Cripe: 377-6398, Twitter: @IDS_BroncoBeat