Allen is 4-0 since Newton was shut down with what has been described as a mild left Lisfranc sprain and is 5-0 as the starter including last year's finale. That makes Allen the seventh quarterback in NFL history to begin his career with five straight wins.
"Just so everybody knows, Kyle will start this week as we go forward," said Rivera, whose team is 4-2 coming off its bye weekend. "For the most part, Cam's going to continue his rehab. He's done a great job. He'll be with the trainers. We're not putting any pressure on Cam [to return]. He's done a great job doing the things we've asked of him.
"He's gone above and beyond as far as working with our quarterbacks and helping them along the way. Until I get something else given to me by the trainers and doctors, he'll continue to do his program."
Regarding a report last week that Newton was healthy and would begin practice this week, Rivera said, "You might see him, you might not."
Rivera reiterated that Newton has been "tremendous" throughout this process.
"It's been very difficult on him," Rivera said. "Here's a guy who has been a competitive young man. But at the end of the day, we've got to be smart, make good decisions going forward. As things progress, we'll let you guys know."
Allen has completed 65.5 percent of his passes for seven touchdowns and no interceptions during the four-game winning streak. However, Rivera said the 49ers (6-0) will be his second-year quarterback's toughest challenge.
San Francisco ranks first in the NFL in total defense, allowing 223.5 yards a game.
"Not just his [toughest], but ours," Rivera said. "This is a very good football team. They're 6-0 for a reason. This will be a very good test for our football team."
Rose: When healthy, Cam should still start
Jalen Rose likes the way Kyle Allen has been playing, but when healthy Cam Newton should still start for the Panthers.