ENGLEWOOD, Colo. --The club's rookie minicamp kicks off today -- one big step toward the start of the 2013 season. With OTAs set to begin in a little more than a week, there's a lot going on at Dove Valley.

This week's mailbag, as usual, touches on a variety of subjects, from players with a chance to prove themselves like Julius Thomas and Mario Fannin to the club's receiving corps, offensive philosophy and first-round pick. Let's get started.

@BBonesteel21 asked: #GrayMatter Decker, Thomas, Welker for sure...how many more WR make the roster, and who do you think it will be?

We went over this exercise with the running backs in the first-ever Gray Matter mailbag, so let's look back at the past five years with regards to wide receivers.

In 2008, Denver kept just four wide receivers on the Week 1 roster. In 2009 and 2010 it was six, then it's been five for the past two seasons.

Taking a look at the Broncos' roster, like you said, Eric Decker, Demaryius Thomas and Wes Welker are sure things. Tavarres King, one of the team's two fifth-round draft picks this year, seems likely to make the team. The fifth spot would seemingly belong to Trindon Holliday, who is listed as a wide receiver but whose main contributions come as a returner. That makes it tough to determine whether the club would count him in its roster cutdowns as a receiver, or whether they'd leave an entirely separate spot open for Holliday.

The NFL is a passing league, but with talent at tight end as well, it seems unlikely the club would keep more than six receivers. So if there is a sixth spot devoted to the position, it would likely be between Andre Caldwell, who was with the team last year, Greg Orton and Gerell Robinson. Orton was on Denver's practice squad last year and Robinson, Brock Osweiler's teammate at Arizona State, spent most of the season on the Cardinals' practice squad.

@KyleCluff asked: Since you're a Tar Heel, what do you think about addition of @Sylwil92?

I'm definitely excited about it. It was fun watching Sylvester Williams wreak havoc in opposing ACC backfields the past two seasons, and I think the Tar Heels are on the upswing. It really was amazing how quickly he progressed from a walk-on at a community college to a two-year starter at a major college program -- where he excelled -- and a first-year draft pick. If anything, it shows how driven he is to be successful and how hard he's going to work now that he's in the professional ranks. But more importantly the Broncos' front office, coaches and players are excited about adding Williams. John Elway has said repeatedly he can be the young anchor of the interior defensive line the team has been craving for a long time, and Director of Player Personnel Matt Russell called him an even better person than he is a player. It's tough to gather much from a rookie minicamp in terms of physicality, especially for a defensive lineman that plays in the trenches, but it will be fun to see him in his orange and blue No. 92 jersey and watch him get started this weekend.

@DangerJonez21 tweeted:
We want to know when the rest of the Broncos will get back at Peyton for all of his pranks.

It's certainly been fun to watch from afar as Peyton Manning has orchestrated a number of pranks on his teammates, from changing the language on a cell phone to hitting Decker with a fake $3,000 invoice to setting Orlando Franklin up to get hit with a plate full of whipped cream at a Rockies game. Joel Dreessen said it just shows how comfortable the players are with one another, and that chemistry is translating to the football field. As far as plotting revenge on Manning, Franklin said it might end up being the whole team carefully planning something to get back at the quarterback. Yesterday on NFL AM, Decker said he's "got some stuff in the works" and he'll make sure it's documented so everyone can share in the laugh. Dreessen said he tried one prank already, setting a loud alarm to go off on Manning's iPad early in the morning, but chickened out because he didn't want to wake up Manning's wife and kids. Regardless, one thing's for sure -- it's going to be tough to prank the mastermind.

@al52perez asked: What will we see different now with Mike McCoy not calling the plays?

Every play-caller has a different personality, but one of the most important aspects of Adam Gase's promotion to offensive coordinator is the continuity the move brings. The offense won't need to change much since Gase was on the staff last year and even called a few plays for McCoy at various times last season. That familiarity can only help Gase's "pedal-to-the-metal" philosophy. This week, Dreessen said the team is already focusing on using less verbiage on every play call so that the team can get to the line and snap the ball that much faster. For the offensive players under Gase, it's less learning a whole new language and more fine-tuning the details. The most noticeable change looks to be that things will move even quicker on offense.

@algolfer68 asked: Any word on Mario Fannin?

Fannin was originally signed as an undrafted free agent in time for training camp in 2011. He was impressing the coaches early in camp but a knee injury forced him to injured reserve. After battling his way back, he was looking to prove himself all over again -- but an Achilles injury during last year's training camp sent him to injured reserve again. Still, it speaks to how the team feels about Fannin's potential that he is still on the roster with a chance to make an impression yet again in this year's training camp. The key for him, obviously, is his health. He was a versatile player at Auburn, where he gained 1,366 yards and 11 touchdowns on the ground, but also set the school's all-time receiving mark by a running back with 985 yards and nine more touchdowns on 97 catches. The Broncos have a lot of depth at running back, but Fannin is a player the coaches and front office seem to like, and he'll have a chance to show what he can do this preseason.

@broncsbomber asked: Is there a chance that J. Thomas sees the field any time soon?

With the lockout shortening the 2011 offseason and an injury limiting him early in 2012, this is the first full offseason for tight end Julius Thomas. Which means it's an important one for the third-year tight end. Just one season of college football made Thomas an enticing-enough prospect for the Broncos to snag him in the fourth round of the 2011 Draft, and his athleticism is clear -- he was a four-year letterman in basketball and helped lead Portland State to its first two NCAA Tournament appearances in school history. Earlier this month, Jacob Tamme said he feels both Thomas and Virgil Green can help the team win as part of a talented tight end group led by Tamme and Dreessen. With Decker, Thomas, Welker, Tamme and Dreessen as the five main targets for Manning, it will take some work to get on the field. But Thomas has a chance to shine in training camp and the preseason now that he's healthy, and can start earning a bigger role.

@dano708 tweeted: I've followed you for a while and just realized your first name is "Gray" not "Gary." The mind only sees what it wants I guess.

Like I told Dano on Twitter, it happens. If people hear my name, they think I said Greg. If they read it, they think I just misspelled Gary. Hopefully this "Gray Matter" thing will help with pointing out that my name is Gray. Unless you all think it's "Gary Matter," in which case you're probably wondering why in the world the mailbag is called "Gary Matter."

As always you can send in your questions for the mailbag to @GrayCaldwell on Twitter. Thanks for all the tweets for this week's edition. See you next Friday.