Let’s not forget that many people had never even heard of this guy until he stepped in for an injured Michael Vick in 2012. He then had a season for the ages in 2013, when he threw for 27 touchdowns and two interceptions. Foles was dealt from Philly to the Rams, who seem committed to making it work with him.
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Dilfer signed as the backup for Tony Banks and the Ravens before the 2000 NFL season. Late into a Week 8 loss, Dilfer came in for a struggling Banks. While many would say Dilfer was a 'game manager' that season, he went on to lead the Ravens to a Super Bowl victory, which they could not have done without him.
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If you thought Tebow madness was insane in 2011 with Denver, then you should go back and study Flutie’s 1998-99 season in Buffalo. He replaced the injured Rob Johnson, when they were 1-3, and worked the 'Flutie Magic' to a 10-6 record.
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Brad Johnson started the season for the Vikings, with the 35-year-old Cunningham well past his prime. Johnson was injured in Week 2. Cunningham went on to set a then-NFL single-season scoring record, went 15-1 and fell only an overtime loss short of the Super Bowl.
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His rookie season, Tommy Maddox started the first three games in 2004, but was mediocre and then got hurt, so all Roethlisberger did was 13-0. He made it 14-0 with an overtime win over the Jets in the divisional round, but then finally lost to the Patriots in the conference title game.
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Williams actually started only two games during the regular season, with the Redskins going 0-2 in both starts. But Williams made his mark in the playoffs. He led the Redskins to a Super Bowl matchup against MVP John Elway. Williams outdeuled Elway, completing 18 of 29 passes for 340 yards and four TDs, and he was named the Super Bowl XXII MVP.
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The Giants drafted Hostetler in 1984 to back up Phil Simms. When Simms broke his foot with three weeks remaining in the 1990 regular season, Hostetler helped the Giants pick up where Simms left off, as they won the remainder of their games, including a 20-19 win over the Buffalo Bills in Super Bowl XXV.
Plunkett is the only player to win a Super Bowl twice as a backup quarterback. Plunkett got his first chance at age 33 when Dan Pastorini broke his leg. Plunkett ended up going 9-2 down the stretch and led the Raiders to a Super Bowl victory.
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When you think of Bradshaw, you don’t think of a backup, but he replaced Pittsburgh's opening-day starter Joe Gilliam six weeks into the 1975 season. Bradshaw helped the Steelers go 10-3-1 in '75 and defeat the Minnesota Vikings 16-6 in Super Bowl IX.
Morrall was the gold standard for NFL backups. He played the entire 1968 season for Johnny Unitas, went 13-1 and won the MVP. In 1972, he started 11 games in a row for Bob Griese, before stepping aside for the Super Bowl that clinched the perfect season.
Rodgers is a perennial MVP candidate, so it is hard to think of him as a backup QB, but that’s exactly what he was for the first three years of his NFL career. Rodgers stepped in when Favre was injured in the second quarter against the Cowboys in 2007. Rodgers completed 18 passes for 201 yards, with no interceptions. Rodgers finally became the full-time starter in 2008.
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You probably have heard of this guy before. The severe Week 2 injury to Drew Bledsoe gave the unheralded sixth-round pick a chance to prove himself. Brady led his team to a Super Bowl win that season, and the rest is history.
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The Niners' acquisition of Young from Tampa Bay in 1987 was one of the NFL’s all-time coups, but it took four years before he snatched the full-time job away from Montana, who was hurt in the 1990 NFC title game. Young went on to lead the Niners to a Super Bowl victory in 1994.
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Favre was a raw prospect when Mike Holmgren took a chance on him after the Falcons gave up on him after one year. He stepped into action in Week 3 when Don Majkowski injured his ankle during the game. He then started in Week 4, and played every game for Green Bay for the next 15 years.
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Few backups have taken their teams to Super Bowls, but Warner won MVP the year he did. This man was bagging groceries and in the Arena Football League before taking over for Trent Green after his preseason injury.