Time is now for Baker Mayfield and Josh Rosen, while wait continues for Jimmy Garappolo

In Cleveland, pure excitement.

In San Francisco, unmistakable anguish.

In Arizona, something in between.

Three NFL franchises, three Week 4 quarterback changes, with the Browns promoting No. 1 pick Baker Mayfield, the Cardinals giving Josh Rosen a try, and the 49ers coming to grips with losing Jimmy Garoppolo.

Garoppolo suffered a season-ending left knee injury with about 5 minutes 35 seconds remaining in a 38-27 loss to Kansas City on Sunday. Beginning in the second half of last season, he had led a foundering franchise back to respectability and relevance.

“It’s a tough injury. I feel bad for Jimmy … it sucks,” Tom Brady, his former teammate in New England, said Monday on his WEEI radio show. “You hate to see someone go down, someone I really like and have been friends with since the day he got here.”

Like Garoppolo, Brady suffered a torn ACL against the Chiefs, his coming in Week 1 of the 2008 season.

The 49ers, who play Sunday at the Chargers, will turn to C.J. Beathard, who started five games as a rookie last season and lost four. He has a connection to the Chargers too, as his grandfather is Hall of Fame executive Bobby Beathard, who was general manager of San Diego from 1990-2000.

At the opposite end of the emotional spectrum are the Browns, who are coming off their first victory in 635 days. Mayfield replaced a struggling Tyrod Taylor against the New York Jets last Thursday and brought the Browns back from a 14-0 deficit to win 21-17.

“There was nothing that I saw that he was not ready to handle,” coach Hue Jackson said Monday in making the change official.

Mayfield, whose first start comes at winless Oakland on Sunday, will be Cleveland’s 30th starting quarterback since the franchise’s rebirth in 1999.

Former UCLA standout Rosen, the 10th pick in this year’s draft, will get the start for 0-3 Arizona at Seattle on Sunday. He replaced starter Sam Bradford in a 16-14 loss to Chicago with 4:31 to play and was unable to lead a comeback. In attempting to put his team in position for a winning field goal, he was intercepted on his first drive. On his second possession, he was sacked to end the game.

“He’s going to have some growing pains,” coach Steve Wilks told reporters. “That happens as a rookie, and you’re going to see some great things from him as well.”

Raise the flag

The Jets play at Jacksonville, and both are coming off humbling defeats. The Jets lost to a Browns team that was 1-32-1 over the past two-plus seasons, and the Jaguars mustered just two field goals Sunday in a 9-6 loss at home to Tennessee.

Both teams have had penalty problems. The Jaguars are tied for the fourth-most accepted penalties (26). The Jets have made mistakes at critical junctures, including two unsportsmanlike calls that helped the Browns stay in the game.

Upside down

What a weird situation in the AFC East, where the Miami Dolphins are two games ahead of the pack at 3-0, and New England, Buffalo, and the Jets are all clustered at 1-2.

The Patriots are coming off back-to-back losses for the first time since 2015, and play at Miami. Of course, after those 2015 defeats to Denver and Philadelphia, the Patriots came back and destroyed the Texans in Houston, 27-6.

This in the 14th time in club history the Dolphins have started 3-0, and they made the playoffs nine of those previous 13 times. The franchise hasn’t won a playoff game since the 2000 season. And here’s an intriguing stat: The Dolphins are 10-1 in Ryan Tannehill’s last 11 starts.

Northern exposure

Buffalo, fresh off a stunning and lopsided victory at Minnesota, gets another NFC North opponent this week with a home game against Green Bay. Packers quarterback Aaron Rodgers, already playing on a tender knee, isn’t feeling any better after getting sacked four times and hit several others in a 31-17 loss at Washington.

“I got a little banged up, but I finished the game and I expect to start next week,” Rodgers told reporters after the loss.

Chief concern

Kansas City plays at Denver on “Monday Night Football,” so the whole country will get a look at Chiefs quarterback Patrick Mahomes, who’s on a record-setting tear.

Mahomes, in his first year as starter, passed for 314 yards with three touchdowns and no interceptions in Sunday’s 38-27 victory over San Francisco. He has 13 touchdown passes (and no picks) in the first three games of the season, surpassing what Peyton Manning did with the Broncos in 2013 when he set the record with 12.

The Chiefs scored 38 points in Week 1 and 42 in Week 2, so they’re the third team in history to score at least 38 in each of its first three games. The 2007 Patriots and 1967 Baltimore Colts are the other two.

sam.farmer@latimes.com

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