Incumbent starter Jeff Backus had been a staple at the position since Detroit selected him as its top pick in 2001. Since that time, 186 games have come and gone -- and Backus has started all of them.
However, he isn't going to be around forever and, at the age of 35, the end of Backus' career appears to be rapidly approaching. Still, the Lions re-signed the veteran tackle during the offseason and with a decade of dependability under his belt, it didn't appear likely Reiff was going to take over as a rookie.
That all changed during Detroit's loss to Green Bay on Sunday, as Backus departed with a hamstring injury, heaping Reiff into the line-up. He'll likely make the start on Thursday's Thanksgiving Day contest, although Backus has officially been ruled out.
"We'll see how he does," said Schwartz. "But it's probably going to be doubtful he'll be able to play on a short week like this."
Backus' Iron-man run for the Lions has been remarkable. He is the franchise's all-time leader in consecutive games started and owns the longest streak among active linemen. Still, no matter how accomplished a player may be, the game waits for no one. Reiff will have to step in if Backus can't play.
Despite being drafted as a tackle, Reiff has bounced around the line throughout the season. He has come in as an extra lineman – essentially a blocking tight end – for much of the season during games and has embodied many different roles during practice.
This week, he'll have his shot at first team left tackle, which should help him prepare.
"I think there's definitely something to it because Riley has been practicing different spots," said Schwartz. "I mean each week on scout team he's practiced in a different spot. To keep his ability to play right tackle, left tackle, guard, any place but center he's practiced. And then also the place he's practiced on offense has been the places he's been running the game. So it definitely gives him a chance to settle in at the left tackle spot and be able to get a week, or a couple days, of stuff like that. But, just like any other player, he was inconsistent at times but did some good things for us and we can all play a little bit player."
Reiff will need to quickly familiarize himself with the position as the team prepares for an unfamiliar opponent.
It's been four years since the Lions have played the Houston Texans and both teams look much different since their 2008 contest.
Outside of countless personnel changes, the Texans have a new defensive coordinator in Wade Phillips, an experienced coordinator who specializes in a quarterback-pressuring 3-4 style of defense.
Reiff can be certain that Phillips will be well aware of his presence on the field and send constant pressure his way. This was the case last week, when Reiff stepped in for Backus. The Packers identified that Reiff was in play and adjusted their deep Cover-Two defense to start pressuring the rookie lineman.
"He's a rookie going into a game; I think any team is going to do the same thing," said Schwartz. "They blitzed to his side an awful lot. (He) got a holding penalty; he's got to be able to hold up. Every player's the same way. Riley's a first-round draft pick – he's a good player. We don't expect any drop off in the game, but it was his first time playing left tackle. We can always do better."
It is unknown when Reiff will take over a full time starting job on the offensive line but it appears as if he will get his first career start on Thursday.
A changing of the guard might be on hold at the left tackle position but a glimpse into the future may be provided on Thursday.