On Wednesday, Marrone was convinced, announcing Manuel had fully recovered from a left knee injury and will start against the New England Patriots on Sunday.
"He's 110 per cent. He looks good out there," Marrone said following practice. "And that's what we're going to go with."
That's a relief for Marrone. He was expressing uncertainty about Manuel's status since the quarterback was hurt scrambling during a 20-16 preseason win over Minnesota Aug. 16.
"Obviously, being a Catholic, there were a lot of prayers to that," Marrone said. "I mean, honestly, you go home and say 'Gosh, I hope he's healthy,' but you really don't know."
Manuel was far more confident he would be ready, especially after taking part in individual drills on Sunday in his first practice since having what the team called a "minor procedure" Aug. 18.
"I felt I would be good to go a few days ago as far as my knee," Manuel said. "I know mentally, if I had the chance to go out and play, I'd be ready for it."
Manuel showed little sign of a limp despite wearing a small brace during practice.
"I haven't had any hesitation," Manuel said, noting he hasn't determined whether he'll wear the brace on Sunday. "It feels fine. It feels strong, so I can do all my normal movements."
He opened practice as he had done in training camp. Taking the snap, Manuel dumped a short pass over the middle to C.J. Spiller, and then took off running without a sign of a hitch toward the end zone with the rest of the starting offence.
Manuel also spent another half-hour throwing passes following practice.
His return is the first bit of positive news for the retooled and rookie-laden Bills, who have been stung by a series of setbacks over the past week.
Starting cornerback Stephon Gilmore will miss the first month with a broken left wrist. Starting safety Jairus Byrd's status is uncertain because of a foot injury and after he missed most of the off-season before signing his franchise tender two weeks ago.
Kicker became an issue after rookie Dustin Hopkins hurt his right groin in practice Monday. Marrone called the injury minor, but ruled Hopkins out from playing Sunday. Dan Carpenter will fill in after the fifth-year player signed Tuesday.
Quarterback has been the Bills' most pressing need over the past two weeks.
Had Manuel not been ready, the Bills would've been forced to start undrafted rookie Jeff Tuel, the only other quarterback on their active roster. Buffalo was placed in this position after veteran free-agent addition Kevin Kolb sustained a season-ending concussion.
The Bills scrambled to add quarterbacks by signing free-agent veteran Matt Leinart and acquiring Thaddeus Lewis in a trade with Detroit. Leinart was cut on Friday, a day after he struggled in a preseason loss to the Lions. Lewis was also cut, but has since been signed to Buffalo's practice squad.
Manuel now gets his opportunity to be the opening-day starter, just as the Bills had envisioned in April, when they selected him with the 16th pick in the NFL draft. The Florida State product was the first and only quarterback taken in the first round.
He arrived in Buffalo with the expectation of filling a position that's been unsettled since Hall of Famer Jim Kelly retired following the 1996 season.
Marrone isn't lowering his expectations with Manuel set to make his NFL debut, and against an AFC East rival that has won 18 of the past 19 games against Buffalo.
"I'd be lying if I'm sitting here saying, 'I don't expect him to do great things,'" Marrone said. "We expect not just EJ, but all of our players that are out there to perform at a very, very high level."
Manuel is a strong-armed and mobile player, who best fits Marrone's up-tempo approach to offence.
In two preseason games, Manuel was inconsistent, but showed encouraging signs of developing as a starter. He went a combined 26 of 33 for 199 yards passing, with two touchdowns and no interceptions.
Center Eric Wood was excited about Manuel's return, and believes the rookie will be ready Sunday.
"I don't think it'll be too big for him," Wood said, noting Manuel had a 25-6 record, including four Bowl victories, at Florida State. "He's got a good head on his shoulders."
AP NFL website: www.pro32.ap.orgSuggest a correction