That came as a surprise to most anyone following the team because Lewis hadn't even secured the starting cornerback job opposite Ike Taylor.
But the coaches never really gave Allen a chance to win the left cornerback position. It was all Lewis all the time throughout training camp, even though he endured a painful shoulder injury.
Lewis was the starter and Allen was the nickel back, and that's the way it has stayed through 10 games.
The result: The Steelers have the top-ranked defense in the NFL, on the strength of the top-ranked pass defense, on the strength of the top-ranked cornerback in passes defensed, Keenan Lewis.
How about some Pro Bowl talk now?
"I don't want to talk about the Pro Bowl," said Lewis. "I'm just trying to play my game and stay humble."
Lewis has little reason to be humble after his play of late. He's broken up 12 passes in the last five games, the games following a narrow loss at Tennessee that would've been averted had Lewis held on to an interception on the Titans' game-tying drive.
"The Tennessee game, he didn't play bad," said Steelers free safety Ryan Clark."But he had a play he felt hurt the team, when he didn't catch the ball. Ever since then he's taken it upon himself to do things to help us win games. It's become really important to him and it's showing on the field."
Clark said that Lewis and Taylor are, "if you take them as a pair, playing better than any two corners in the league."
Lewis's rise has coincided with Taylor's rejuvenation as the team's shutdown corner. Taylor, for instance, in the Baltimore game, was assigned the task of taking speedster Torrey Smith out of the Ravens' passing game. And he often had safety help over the top.
So QB Joe Flacco picked on Lewis, who allowed Anquan Boldin and Jacoby Jones to catch 8 of the passes thrown at him, but for only 62 yards. Pro Football Focus determined that Lewis gave up only 9 of those 62 yards after the catch.
Lewis is fast, physical and finally playing with confidence.
"He's doing an amazing job," Clark said. "He's really starting to take just every play personal. He's challenging guys, anybody he's facing. He's going out there with confidence."
Clark was asked to pinpoint one play by Lewis that stands out, and what came to mind was the first snap of the win three Sundays ago in New York.
"The way we started the Giants game," Clark said. "Eli (Manning) takes a shot down the middle of the field and Keenan's one-on-one with Hakeem Nicks, a guy we know can go up and get the ball. He makes that play early. If he doesn't make that it changes the course of the game, it changes the way the game flows. He started us off on the right track there and that's a play that kind of stands out to me. But he's made tons of plays all year."
Lewis hasn't completely overcome his shoulder issue, but says "Everyone's sore at this point in the season, so now I'm on an even playing field."
He attributes advice from Taylor for keeping his body strong as the season has wore on. Taylor advised Lewis to force himself to get out of bed Monday mornings after games to lift weights.
"The last couple of years I was like, ‘Nah, I'm tore up on Monday. I ain't lifting no weight,'" Lewis said. "But this year it's helping. It's been playing a big role in me staying healthy and strong out there. I take my tips from him."
If Lewis keeps learning from Taylor, he – both of them – might just make a wild spring prediction come true.