PITTSFORD, N.Y. -- Travel to most NFL training camps, and this passing drill is the same: A ball boy snaps to a quarterback, who throws to a receiver practicing a specific route.

But make a stop at St. John Fisher College in upstate New York, site of the Buffalo Bills' training camp, and rookie quarterback EJ Manuel isn't receiving the ball from just another member of the equipment staff.

Instead, you'll see head coach Doug Marrone snapping it to Manuel.

It's appropriate, because the fate of Marrone, a former NFL offensive lineman, will be tied to the success of Manuel, the first quarterback chosen in April's draft.

Through his first week of an NFL training camp, Manuel has looked the part, avoiding the critical mistakes that rookie quarterbacks often make as the intensity of practice picks up.

Which raises the next point: These Bills want to play fast.

Offensive coordinator Nathaniel Hackett installed a no-huddle offense last season while working under Marrone at Syracuse, and will bring the same concepts -- borrowed from the Bills' "K-gun" offense of the early 1990s -- to Buffalo.

As training camp rolls on, Manuel has been eased into the first-team offense in practice, and he appears comfortable running Hackett's up-tempo system. Having poise in practice is one thing, though, and expecting Manuel and Hackett, who was last in the NFL as a quality control coach with the Bills in 2009, to light up NFL defenses this season is probably asking too much.

The Bills want to bring Manuel along slowly, and there will be growing pains along the way. So despite the rookie's passing the first few tests of training camp, don't look for Marrone to accelerate the process too much.

But for now, it's so far, so good for the 16th overall pick out of Florida State.

"He's going to be the face of our franchise," general manager Doug Whaley said. "And it's not too big for him."

THREE HOT ISSUES

Mario Williams was bothered by a wrist injury in 2012, and this year he has already missed time in training camp with a sore foot. AP Photo/Bill Wippert

1. Can they stay healthy? When the Bills took the practice field for the first time last weekend, nearly the entire roster was able to participate in practice, leading Marrone to note afterward how the team was fortunate to begin camp that healthy. Yet defensive end Mario Williams was one of the few exceptions, watching from the sideline because of a sore foot. He later left camp to have it examined by doctors, and the Bills' highest-paid player had not returned to practice by Friday.

Last season, Williams dealt with a wrist injury that limited his productivity until he underwent a procedure during the bye week. He came back strong, finishing with 10.5 sacks. But the Bills need more out of him, and his latest injury isn't a good sign for the team.

Likewise for wide receiver Steve Johnson, who pulled up with a hamstring injury during Friday's practice, and could miss time this preseason. The Bills dealt with a number of injuries to key players last season -- tight end Scott Chandler and running back Fred Jackson among them -- and they haven't built enough depth on their roster to withstand the blow of losing a player like Johnson.

2. When does Byrd return? Safety Jairus Byrd remains unsigned and away from Bills training camp, another less-than-ideal situation for one of the team's top players. The Bills failed to reach a long-term deal with Byrd, who is the only franchise-tagged player in the NFL yet to sign his tender, by the July 15 deadline.

Ultimately, it would be surprising if Byrd doesn't report to the team by the start of the regular season. By doing so, he would earn a guaranteed $6.9 million, and still have the possibility of a long-term deal come next March.

The question is if the Bills can persuade Byrd to return earlier, forgo the risk of injury and use the preseason to get acclimated to the new defensive scheme. But one way or another, these situations tend to work themselves out, and Pro Bowl-caliber players like Byrd quickly get back up to speed.

3. Can Pettine turn around the defense? It didn't take long last season for the Bills' porous defense to be exposed. The New York Jets, owners of the NFL's 28th-ranked scoring offense by season's end, hung 48 points on Buffalo in the season opener. Three weeks later, the New England Patriots erased a 21-7 third-quarter deficit to come away from Orchard Park with a 52-28 win, lighting up the Bills for 580 total yards.

Such performances, especially against division opponents, will drown the Bills again this season if new defensive coordinator Mike Pettine can't turn things around. Pettine is known for blitz-heavy schemes that pressure opposing defenses, but his defensive remake will also have to address a run defense that allowed opponents 145.8 yards per game last season, second-worst in the NFL.

Pettine has several pieces to work with, including Byrd, Williams and top cornerback Stephon Gilmore. The key will be filling holes elsewhere. Can rookie Kiko Alonso step in right away at inside linebacker? Can former third overall pick Marcell Dareus benefit from a fresh start and contribute along the defensive line? And where does the pass rush come from if Williams goes down with another injury? These are just a few of the questions facing Pettine and his staff.

REASON FOR OPTIMISM

Beyond the early positive signs from Manuel, the Bills' offense has the potential to be explosive, especially if healthy. They addressed deficiencies behind Johnson at wide receiver by drafting Robert Woods (second round) and Marquise Goodwin (third round). They have one of the NFL's better running backs in C.J. Spiller and a receiving threat at tight end in Chandler. The offensive line could prove problematic, but Hackett's fast-paced system could help take pressure off blockers.

Having not made the playoffs since 1999, the Bills' annual problem is getting over the hump in their division, which includes defeating New England. They will host the Patriots at Ralph Wilson Stadium in the Sept. 8 season opener, which is perfect timing for Buffalo. Fans will be excited, parts of Hackett's offense will yet to be revealed on film and Patriots tight end Rob Gronkowski may not be ready to play. It will be a challenge for Buffalo, but kicking the season off by beating New England would be big.

REASON FOR PESSIMISM

The NFL saw three rookie quarterbacks take their teams to the playoffs last season, but it's hardly been an annual occurrence. Manuel will need to exceed expectations if he is to repeat the successes of Robert Griffin III, Russell Wilson and Andrew Luck from last season. It won't doom his career if Manuel struggles for stretches this season (assuming he becomes the starter) and the results for the Bills follow suit. It's just the way things go in the NFL, and improvement can take time.

Beyond that, the Bills have a top-heavy roster that will require more than one season under Whaley to develop depth across positions. The offensive line lacks starting-quality players at at least one position, there are question marks behind Chandler at tight end and the defensive line includes several underachieving, younger players. The rigors of an NFL schedule may prove too difficult to overcome for the weak points on the roster.

OBSERVATION DECK

The Bills drafted EJ Manuel (left) in the first round, but Kevin Kolb has been ahead of him in taking most of the first-team reps at quarterback during camp. AP Photo/David Duprey

• For all the talk about Manuel, it has been veteran Kevin Kolb taking the majority of the first-team reps at quarterback in camp. The Bills have dismissed talk of Kolb being a "placeholder" while Manuel adjusts to the NFL, but Kolb will have to step it up if he wants a legitimate shot at holding onto his role as the starter. He has struggled, and would hardly inspire confidence if under center on opening day.

• Spiller had a breakout season in 2012, but don't overlook Jackson, who could create an impressive one-two punch at running back. Jackson is 32 and coming off a knee injury that lingered last season, but is just two years removed from averaging 5.5 yards per carry in 2011. The Bills have used two-running back sets frequently in practice, and between Spiller, Jackson and Tashard Choice, they have backfield threats that will force defenses to adjust.

• The battle at wide receiver behind Johnson has several candidates, and the Bills haven't been afraid to throw different players into the mix with the first-team offense. From this standpoint, Goodwin has performed better in camp than Woods, who struggled with drops through the first few practices. Undrafted rookie Da'Rick Rogers figures to factor into the mix as well. It's no coincidence the Bills opened their first practice of training camp with a deep-ball drill; it's a receiver group that has the potential to take the top off of opposing defenses.

• Marrone has routinely named Jamie Blatnick and Kourtnei Brown when mentioning pass-rushers on his defense, especially following the surprising release of Mark Anderson shortly before training camp. But it may be more out of default than anything: the Bills lack depth at the outside linebacker position. Blatnick spent most of last season out of football after being released from Denver's practice squad, while it took Brown until Week 14 to hook onto Washington's practice squad. It's possible either player could emerge, but if Marrone has practice-squad-level players on the field to provide pass-rush during the regular season, the Bills will be in trouble.

• It's a similar situation along the defensive line, where the Bills are searching for options both alongside and behind Mario Williams and Kyle Williams. The top option is Dareus, but the Bills will need more quality play out of him if he takes 50 percent or more of defensive snaps. Other possibilities include more players who have largely underachieved in the NFL, including Alex Carrington and Alan Branch.

• The absence of Byrd in practice has been alleviated by an impressive start by Aaron Williams, the team's second-round pick in 2011. He struggled at cornerback through his first two seasons, but his switch to safety looks to be paying off early in camp. He has been around the ball and come down with interceptions.