Former Defensive Rookie of the Year Jerod Mayo is entering his third season, and Gary Guyton has been with the Patriots the same amount of time. The pair is joined by Tyrone McKenzie, a third-round pick last year who missed the season because of a knee injury, Thomas Williams, a member of the practice squad last year, and rookies Brandon Spikes and Dane Fletcher.

“I think all of them have done well,’’ coach Bill Belichick said yesterday. “Some of the linebackers are a little more [capable of playing] first and second down, some of them are a little more third down. Some of them are probably a little more of the kicking game. Some might have a combination of all three.

“So, I think players have different values and different strengths in what they can bring to the team. But [they’re] all competitive in their respective areas.’’

Mayo did not duplicate his impressive rookie season last year, in large part because of a sprained right medial collateral ligament he suffered in the season opener and rushed back from, missing just three games for an injury that usually takes 4-6 weeks from which to recover.

A captain last year, Mayo is capable of playing in nearly every situation, so the competition is mainly to see who plays alongside him. Guyton started all 16 games last season after Tedy Bruschi’s retirement, and was getting most of the snaps with the first team during the first days of camp, before slipping in coverage and hurting his knee Sunday.

A league source termed it a “tweak’’ and not serious, but Guyton has not been seen on the field since.

Without Guyton, there is an opportunity for Spikes and McKenzie. It is Spikes who is now most often paired with Mayo; during spring camps he was calling plays with the reserve defense, being asked to take a leadership role nearly from the day he arrived.

McKenzie is looked at as a thumper in the run game, and only bolstered that belief with his hole-filling, pads-cracking hit on Laurence Maroney Friday morning. After spending all of last year learning as he rehabbed, McKenzie has relished the opportunity to put his lessons into action.

“It’s tough when you sit in the classroom all year and just learn and learn and learn but never put it into play,’’ McKenzie said. “It’s a whole different situation . . . [organized team activities] were huge for me just to learn it and to go out there and put it on the field.’’

Belichick lauded McKenzie’s maturity when he drafted the former South Florida standout, and took the chance to mention his football intelligence yesterday.

“Tyrone is a smart kid. He really understands the defense. He’s good with the calls and the communication and adjustments and really understands what we’re doing,’’ Belichick said. “He just needs the practice repetitions of actually doing it, taking on blockers, reading keys.’’

Linebackers especially must rely on their instincts, to read and react to what is happening in front of them in a split second.

McKenzie is a bit rusty, but Spikes’s instincts are finely tuned. The big knock on him coming out of Florida was that his 40-yard dash time was slow. But given his ability to more often than not anticipate what’s going to happen, his lack of speed is less of an issue.

“He sees some things that I’m not sure everybody sees,’’ Belichick said. “He’s an instinctive player and he sees things. I don’t know if they are exactly the textbook way you would read the plays, but he reads them. It’s interesting to kind of work him into our system.’’

Spikes, a second-round pick, said he trusts his eyes, then tries to attack.

“Whatever I see and read, I go,’’ he said. “That’s what gets me by there. I just try to play the game the old-school way. Guys [who] just played aggressive, downhill kind of linebackers, I just try to mold myself after that.

There is competition on the field, but the inside linebackers are trying to beat each other even in the classroom. McKenzie likes to irritate Mayo — who could be considered the “elder statesman’’ of the group at 24 — by answering questions from the coaching staff before he does.

“Jerod will get ready to say the answer, but before he gets a chance I jump in front of him and say it because I want to learn as much as he does,’’ McKenzie said. The never-ending competitiveness is just “guys enjoying the game of football that we have an opportunity to play, we’re blessed to play.’’

If the young inside linebackers continue to develop at their current pace, Belichick will have plenty of options.

Shalise Manza Young can be reached at syoung@globe.com. Follow her on Twitter @shalisemyoung.