The San Francisco 49ers were dealt a heavy blow when quarterback Brock Purdy re-aggravated his injury. However, the 49ers are 3-0 in his absence after backup quarterback Mac Jones' surprising emergence.Jones, who signed a two-year, $7 million deal with San Francisco in the offseason, has thrived in coach Kyle Shanahan's system. He was instrumental in the 49ers' 26-23 overtime win at the Los Angeles Rams on Thursday, helping the team to a 4-1 start.With the 49ers flying in the league under Jones' offensive leadership, rumors have started of a potential dilemma in the quarterback room. NFL insider Grant Cohn is among the people who believe the 49ers are better off with Jones as QB1, as he gives the team a "new identity" with his passing game."Here's why the 49ers quarterback controversy is legit on this team this season," Cohn said on X. "Mac Jones gives them a better chance to win than Brock Purdy and that's because they can't run the football; they have a new identity. They have to be able to drop back and pass 50 times and not turn the ball over and that's not Brock Purdy. It's never been Brock Purdy."If Brock Purdy drops back 50 times, he's probably going to throw at least one, maybe two interceptions, because he doesn't see the field that well. He's much better holding onto the ball, making a guy miss, avoiding a sack and trying to make plays. That's his game."NFL insider believes 49ers should stick with Mac Jones' passing game over Brock PurdyMac Jones completed 33 of his 49 pass attempts for 342 yards with two touchdowns and without any interceptions. Grant Cohn highlighted his performance against the Rams on Thursday, saying it is what San Francisco needs."You need the quarterback and the passing game to be the focal point of the offense and that's what Mac is doing so well," Cohn said. "He really went through LA 49 times to backups, threw no picks and won. As long as he can keep doing that, it doesn't matter how much the 49ers are paying Brock Purdy, Mac is your starting quarterback."While Cohn might believe Jones could be the starter even if Purdy is available, the 27-year-old revealed that he signed to be Purdy's backup and is willing to go back to his QB2 role once the 49ers have their star quarterback available.