Lewis, the starting quarterback only after an injury to EJ Manuel, took a jarring hit from behind on the first play of the Bills' 35-17 loss Sunday in New Orleans, staying on the ground for over a minute before coming to his feet.
Although the ball squirted loose and was recovered by the Saints, Lewis remarkably did not miss an offensive play. Two weeks after playing through a foot injury that left him with a bad limp afterward, Lewis showed Sunday the grit that has in some ways defined the Bills' season.
"There was no doubt in my mind that after the very first hit that I was going back in the game," he said. "It's like you're going to battle. You're either going to turn your back on them or you're continue to fight for them. That's my mentality and I'm going to keep it that way."
It's a mentality that seems to have spread across the Bills this season, one that has featured significant injuries -- more than just nicks and bruises -- to almost every one of its key players.
"The [toughness of the] coaching staff and the whole team, it just rubs off on us," Lewis said.
"I know [Lewis] was hurting. A lot of guys were hurting," wide receiver Stevie Johnson said. "We wouldn't expect anything less from Thad [to return]. This is an opportunity... unless it was a broken leg, I'm sure he'd be out there. That's the type of guy that he is. He's ready to fight for his boys."
Healthy or not, however, Lewis was overmatched Sunday.
It's no fault of his own. For starting a quarterback who wasn't on their roster for most of the preseason, the Bills are doing about as well as any team could hope. But unless they got help from defense or special teams, they weren't going to win a shootout with Drew Brees.
Indeed, a shootout it became. After the defense was able to make some early stops, the Saints' offense kicked into gear late in the second quarter, more than doubling their yard total on a 69-yard touchdown catch by Kenny Stills.
Brees finished 26-for-34 for 332 yards, five touchdowns, and no interceptions, along with a sizzling 146.1 QB rating.
"We know the type of offense they have," Johnson said. "I don't want to say that no team can shut them out, but we had to hope to contain them and offensively we had to put up points. I felt like our defense did [well] for the most part. We have to pick up the slack a little more."
If the Bills' offense wants to someday go toe-to-toe with Brees, one area where they can improve is in pass protection. Lewis was sacked four times Sunday and hit numerous other times. His first fumble came on a designed run, but his second came on a 13-yard sack by defensive end Cameron Jordan.
"There's nothing you can do about it when you are about to throw the football and a guy is standing there and hits you," Lewis said. "Yeah, the first was on me but the next ones when you get a little pressure and you get ready to throw the football, the defense just makes a great play."
Head coach Doug Marrone said the Bills used more "zero" coverage -- a blitz look with no zone coverage in the middle of the field -- than they were expected.
"They brought some blitzes," center Eric Wood said. "But it was nothing that we were unprepared for, I don't think. Nothing we shouldn't have been able to handle."
"It was a little more than what we expected," Lewis said. "But they weren't tipping their hand. So they weren't showing us they were in zero-blitzes. It was after the snap."
Overall, Lewis has been sacked 13 times since taking over the starting job three weeks ago.
"There's protection break downs in our end," Wood said. "And [Lewis] is trying to make some plays with his legs. We went the last couple years in the bottom of the league in sack numbers and we didn't get wins. I think he's just trying to make more plays."
Lewis wasn't able to connect on any completions longer than 26 yards Sunday, one reason why the Bills couldn't keep pace with the Saints, dropping them to 3-5 on the season.
"You can't win without making plays," Lewis said. "If we made more plays, the score might have been different."