Rivers threw two more interceptions, including a pick-six, and was called for intentional grounding while in the end zone -- leading to a safety -- in Indianapolis' 32-23 loss to the Cleveland Browns on Sunday.
"No consideration of [replacing Rivers with Jacoby Brissett]," Reich said. "Philip is our quarterback."
The Colts signed Rivers to a one-year, $25 million contract last spring in hopes that the 38-year-old would bring some steadiness to the quarterback position after Brissett struggled last season.
Rivers, however, continues to have turnover problems. He has thrown more interceptions (five) than touchdowns (four) this season. His 28 turnovers since the start of 2019 are the third most in the NFL behind New Orleans Saints quarterback Jameis Winston (35) and New York Giants quarterback Daniel Jones (31).
Four of Rivers' five interceptions have come in the Colts' two losses this season. The Colts have scored only eight offensive touchdowns, while attempting 17 field goals.
"We just haven't executed well enough," Rivers said Sunday. "If we knew the exact answer, we would have already solved it."
Reich was adamant after the game in saying that Rivers is "playing really good football. That's the least of my worries."
The Colts coach backed off that statement Monday.
"I admit that the statement I made was dramatic and probably overdone," Reich said. "My apologies for that statement. Not the best statement."
The Colts knew what they were getting from Rivers when they signed him.
They're at their best when they're able to lean more on their defense, which is ranked No. 1 in the NFL in yards allowed (266.0), and their running game. Not when they're relying on Rivers' right arm, even if he became just the sixth quarterback in league history with at least 400 touchdown passes and 60,000 passing yards.
The Colts are 0-2 with Rivers throwing only one touchdown and those four interceptions while attempting 30-plus passes in each loss.
"My trust at the end of the day is who he is, this guy is a Hall of Fame quarterback and I have the upmost confidence and belief in him," Reich said. "Our team has the upmost confidence and belief in him, and you have to live with those mistakes. The good is going to far outweigh the one or two bad things that happen. We have to be a good enough team to overcome the one or two bad moments."