Rivers takes over as the Colts' signal caller after an offseason full of evaluations by general manager Chris Ballard and head coach Frank Reich.

While Jacoby Brissett performed admirably in the face of great adversity after the sudden retirement of Andrew Luck just before the start of the 2019 regular season, both Ballard and Reich said they were going to consider all options at the quarterback position this offseason, both in free agency and the draft.

The team knew Rivers was going to be one of many quarterbacks available in what has amounted to an unprecedented free agency period to start the new league year; already names like Tom Brady (Tampa Bay Buccaneers), Teddy Bridgewater (Carolina Panthers), Nick Foles (Chicago Bears), and Marcus Mariota (Las Vegas Raiders) have joined, or are expected to join, new teams, either via free agency or trades. Jameis Winston, meanwhile, remains unsigned, while Drew Brees (New Orleans Saints) and Ryan Tannehill (Tennessee Titans) signed deals with their previous clubs, and the Carolina Panthers have announced that they have given Cam Newton permission to seek a trade.

In the end, however, the Colts just couldn't pass up on Rivers' familiarity with Reich and offensive coordinator Nick Sirianni.

The three worked together for three seasons with the Chargers from 2013-15 when Reich was quarterbacks coach, and then offensive coordinator, while Sirianni was an offensive quality control coach before being promoted to quarterbacks coach.

Rivers had one of his best-overall seasons as a pro in 2013, throwing for 4,478 yards and 32 touchdowns; he led the NFL in completion percentage (69.5) and was fifth in yards per pass attempt (8.2) and fourth in passer rating (105.5) and was named the NFL's Comeback Player of the Year.

In total in Rivers' three seasons under Reich and Sirianni with the Chargers, he ranked, on average, second in the NFL in completion percentage, fifth in passing yards, fifth in touchdown passes, sixth in passer rating, seventh in fewest interceptions and ninth in yards per pass attempt.

Rivers clearly made an impression on the future Colts head coach and offensive coordinator.

"Philip is an elite quarterback in this league. He has proven that year in and year out. He is a tough competitor," Reich said Sept. 4 as the Colts were preparing to open up the 2019 season against Rivers and the Chargers. "He is everything you want in a quarterback. He is elite – elite accuracy, elite toughness, playmaking (and) a really good challenge for our defense."

Said Sirianni: "The great quarterbacks of the league all have two things: they have timing and accuracy. I think that's what all of them have. The arm strength varies, the motion varies, all those things vary. But the timing and the accuracy and the vision of the field to be able to see the whole field and make plays that way. Every one of the top-five quarterbacks, top-eight quarterbacks have those traits and that's what he has."