Todd Davis comes into training camp with the most experience, with four regular-season starts over the last two seasons.
But the progress of Davis, Corey Nelson and returning practice-squad linebacker Zaire Anderson was palpable enough for the Broncos to avoid targeting an inside linebacker in the draft to replace free-agent departure Danny Trevathan.
"It felt good. It just showed the linebacker corps that they have faith in us," Davis said in May. "All the linebackers they have here, they feel like they have a complete group, and they'll move forward with the season."
With Marshall sidelined during OTAs as he recovered from a dislocated finger, Davis and Nelson played alongside each other throughout those four weeks of practices, and did "really well," Defensive Coordinator Wade Phillips noted.
"We feel like we've got a good rotation if we have to or if one of them steps up and plays all the time," Phillips said during OTAs. "We can do both."
But Davis' advantage could rest in how he improved from his 2014 starts to the two he made in 2015.
"I think I learned situational offenses a little better," Davis said. "Kind of what the offense wants to do, and the position they want to put themselves in. I feel like being able to get those starts helped me understand their game plan a little bit better."
Further, Davis brings an unusual intensity to his role -- so much that Phillips sees echoes of the relentless Chris Spielman, whom he coached in Buffalo from 1996-97.
"He reminds me of the same kind of temperament," Phillips said during OTAs. "He's intense every play on the field."
Nelson has been a steady special teamer the last two seasons while contributing spot work on defense.
"There is a lot of stuff I have to work on," Nelson said during OTAs. "Being able to learn how to shed blocks and being able to learn how to drop in coverage the right way, depending on the call and the little checks that we have within a call, there are a lot of things to get better at while I'm running with the [first team]."
Anderson is the wild card. He had an impressive training camp last year to earn a practice-squad spot, but good health at inside linebacker prevented him from getting a promotion to the 53-man roster.
MORE 20 QUESTIONS:
•1. How will they replace Malik Jackson?
•2. What will Roby provide in his third year?
•3. What's next at long snapper?
•4. Will DT have a bounce-back season?
•5. What must Heuerman show this summer?
•6. Will Green show he can be the No. 1 option at TE?
•7. Who could start a new undrafted streak?
•8. How long will it take the new OTs to get up to speed?
•9. Who could emerge to handle kickoff and punt returns?
•10. Who will be the No. 3 safety?
•11. Are Barrett and Ray ready for bigger roles?
•12. Who emerges as the No. 3 WR behind Thomas and Sanders?