On the intensity scale, the Bills coaching staff gets to turn it up a bit Tuesday, when Organized Team Activities begins. It's the next phase of the offseason. And while the intensity level won't get anywhere near Spinal Tap's "11," the uptick should be noticeable.

The team has had five weeks of Voluntary Offseason Conditioning since early April, sessions that include individual instruction and drills, but no offense versus defense team drills. The veterans also had a three day voluntary minicamp three weeks ago. Starting Tuesday, the Bills will have three weeks of Organized Team Activity, workouts that can include 7-on-7, 9-on-7, and 11-on-11 offense versus defense work, but no live contact. All of the workout limitations are established by the Collective Bargaining Agreement.

So with the Bills offense lined up against the Bills defense, it will be possible to keep an eye on some roster battles over the next three weeks. Here are six questions about the Bills headed into the OTAs:

1. WHO'S UNDER CENTER?

It's a wide open, three way battle, between EJ Manuel, Matt Cassel, and Tyrod Taylor. And the Bills coaching staff insists no decision has been on a pecking order at the critical position.

Offensive Coordinator Greg Roman says going into the OTAs, there's no "leader in the clubhouse" when it comes to the quarterback spot.

"I think it's too early to say," Roman says. "We haven't got on the field with the defense, except for that first minicamp, which was purely exploratory on our part. We were going to see where guys where we at, and now let's get our hands on them and see where hopefully we can take them. Once we get through OTAs I'll probably have an opinion. But that one, I will keep that under my vest."

The Bills are determined to keep the QB reps pretty even among the three contestants, by employing two different "starting" offensive units during the workouts.

2. HOW DOES THE O-LINE LINE UP?

The Bills are likely to have two new guards with the starting unit at the beginning of OTAs, two players who weren't even on the roster last year.

Veteran Richie Incognito and rookie John Miller are expected to get the first team reps up front. Which side they play, right or left, is still unknown.

Miller has impressed the Bills coaching staff in the handful of workouts he's been involved in since the Bills picked him in the third round of the draft. The Louisville product has been especially impressive with his work in the classroom, according to Offensive Line Coach Aaron Kromer.

"Is John Miller learning quickly? I would say yes," Kromer says. "He has a good background coming out of college and when we interviewed him for the draft we knew that he had the ability to learn quickly and to adapt a technique just through our interviews. So it's been a good start, but it's only a start and we have a long way to go."

It's not just the lineup at guard that will see some shuffling. Kromer says the offensive tackles will shift from the left side to the right side as well. And he cautions against reading too much into the offensive line setup, based on what's on the field the next three weeks.

""OTAs will be the next step and not the ultimate step," according to Kromer. "An offensive lineman earns his stripes in training camp and preseason and as the season goes in games. It's going to be a while before we really know who those five are, but the more times you approach to block the right way, block the right guy, use the right technique, the more opportunities each guy will get."

3. WHO GETS THE WORK AT RUNNING BACK?

When the regular season begins, LeSean McCoy who will be workhorse. The Buffalo coaching staff has been saying that since they picked up "Shady" in a trade in early March. But the roles for veterans Fred Jackson, Boobie Dixon, and Bryce Brown are undefined. And rookie Karlos Williams is likely to factor into the RB equation also.

Brown is behind the rest of the backs, according to his position coach, Anthony Lynn. He's been missing the offseason workouts for personal reasons. But there are plenty of backs to work with. And even though from an outside perspective, it may seem like a crowded field at the running back spot, that's not the way Coach Lynn sees it.

"I love the combination and the skill set that we have in the backfield right now," he says. "Training camp is a hard process. It's a lot of reps, a lot of hits and when you're going to run the football you can't have enough good backs in my opinion."

4. WHO'S IN THE MIX AT SAFETY?

It looks like 3rd year man Duke Williams has a leg up on the competition at safety opposite Aaron Williams. But the Bills are probably going to take a look at some other candidates at that position in the weeks ahead.

Head Coach Rex Ryan says the job will not be handed over to Duke Williams. "There will be competition there," he says.

"I think Duke is a guy who has the physical traits you look for," according to Ryan. "He loves to play. He's a tough, physical guy and he can run. Those are obviously some main traits you look for. How quickly he processes we'll find out. There's probably competition in this building and that will be good for Duke and good for our football team."

The competition from inside the building includes Jonathan Meeks, Bacarri Rambo, and even 2nd year man Kenny Ladler, who saw special teams action in three games last year, before going on injured reserve. Veteran DB Corey Graham could also get some looks at the safety spot.

5. WHO FILLS OUT THE DEPTH CHART AT WR?

The Bills look talented, deep, and young on the depth chart at wide receiver. And the top three spots on the chart are locks—Sammy Watkins, Robert Woods, and Percy Harvin.

After that, there are several wideouts with different sizes and skill sets that will make the decisions at the position interesting. The Bills have blazing speed in the person of Marquise Goodwin and Marcus Thigpen. There's size to choose from, when you look at veteran Marcus Easley and 7th round draft pick Dezmin Lewis. And reliable production from the likes of Chris Hogan.

Special teams will be key in determining the fourth, fifth and maybe sixth WR spots. Easley is a Pro Bowl caliber special teams ace. Goodwin, Harvin, and Thigpen are dynamic return men.

6. TIGHT RACE AT TIGHT END

The Bills targeted free agent Charles Clay in free agency and spent big money to bring him to Buffalo. But after Clay, the tight end picture is not especially deep.

Sixth round draft pick Nick O'Leary has impressed the coaches in his first couple of weeks of practice. After O'Leary, there are a couple of veterans with limited experience—Chris Gragg and MarQueis Gray. And then rookie Chris Manhertz, who's attempting the difficult transition from basketball to football.

Buffalo's new offense employs multiple tight end sets. The coaching staff is likely to use the OTAs to find out which of their untested candidates help at the position.