The “face of the franchise” in the N.F.L. is nearly always the team’s quarterback. In an odd twist, as the playoffs begin this weekend, a few of the teams will find out what happens when that face belongs to someone doing on-the-job training.

To one extreme of experience is Sunday’s matchup between the Giants and the Green Bay Packers. It is a duel between Eli Manning and Aaron Rodgers, seasoned quarterbacks who have combined to play 368 games, attempt 12,305 passes and win three Super Bowls.

Contrast that with Saturday’s game between the Houston Texans and the Oakland Raiders. Brock Osweiler, just a few weeks after being benched, will start for the Texans because the team’s preferred starter, Tom Savage, is out with a concussion. Osweiler’s 21 career starts make him a wily veteran compared with the Raiders’ starter, Connor Cook, who, thanks to injuries to Derek Carr and Matt McGloin, will be the first quarterback to have his first N.F.L. start come in the playoffs.