LONDON -- The St. Louis Rams had won four straight games under Marc Bulger in 2002 when speculation began about when Kurt Warner would return from a broken pinky. The streak reached six in a row before the switch back to the reigning NFL MVP.

Coach Mike Martz never wavered.

“It’s a real easy decision for me,” he said at the time. “Kurt’s our quarterback. I’m telling you, he is our quarterback. Marc Bulger is outstanding, but Kurt is our quarterback.”

It’s not always that easy. In 2001, New England coach Bill Belichick named relatively unknown Tom Brady his starter the rest of the season when veteran Drew Bledsoe was ready to return. Brady led the Patriots to the first of six Super Bowl victories.

Decision time for the Carolina Panthers is coming for coach Ron Rivera on whether to stick with Kyle Allen when 2015 NFL MVP Cam Newton is ready to return from a mild Lisfranc injury. The decision is now more difficult than anyone might have imagined four weeks ago.

Allen has led the Panthers to four straight wins after an 0-2 start under Newton. Allen is 5-0 overall, making him the seventh quarterback in the past 25 years to begin his career with five victories. He’s the only one of that group to go 5-0 without throwing an interception.

After Sunday's 37-26 victory over Tampa Bay at Tottenham Hotspur Stadium, Rivera simply could have said that Newton would be his starter when he’s ready to return. At the start of this journey with Allen, Rivera said that would be the case.

Instead, he said his way of dealing with the situation was not to answer the questions that will continue to come when Carolina returns from a bye week.

“I’m not going to worry about it,” Rivera said. “I’m not going to speculate on anything until I have to address that. So until then, we’re going to stay in the now, stay in the focus of what we’re doing right now.”

What the Panthers are doing is winning, and the're having fun doing it. They should let Newton sit on the side until Allen loses a game, maybe two. They should give Newton time to make sure the injury is fully healed even if Newton believes he could play if needed.

It’s an uncomfortable situation for Rivera and everyone involved.

Since he was picked with the No. 1 pick of the 2011 draft, the mantra has been how Newton goes, so go the Panthers. Now it seems almost taboo to mention his name.

Coaches and players don’t like messing with a good thing when they’ve got it, and right now the Panthers (4-2) have a good thing going with Allen.

“He’s doing a great job,” tight end Greg Olsen said. “It’s hard to win in this league. People go round and around in circles ... but at the end of the day, he’s won four games in a row. Three have been away from our home field, which is hard to do in this league.”

Asked what it will look like when Newton is ready to return, Olsen didn’t want to get into that -- and you can’t blame him for that.

“To speculate, until Cam’s healthy, back practicing and playing, to dive into hypotheticals doesn’t do anybody any good,” he said.

Running back Christian McCaffrey did his best not to spark a controversy, but in doing so he sounded almost controversial when asked what the team will look like when Newton is ready.

“It’s not my decision,” he said.

One reason Pro Bowl defensive lineman Gerald McCoy signed with Carolina during the offseason was for a chance to play with Newton. He insisted he’s not surprised to be 4-0 with Allen.

“Listen, I’ve been a fan of Cam for a long time,” McCoy said. “But the biggest reason I came to this team was how resilient they are. ... Kyle’s been doing everything necessary to help us win. As long as he’s in, we’re riding with him.

“If Cam comes back, we’re riding with him. You step on that field, we’re with you.”

Notice McCoy said “if,” not when.

Allen was asked the same question.

“I don’t know,” he said on what the team will look like.

Allen doesn’t know because nobody knows what things will look like if Newton returns. He's riding an eight-game losing streak, dating to last season.

The Panthers know what things look like now.

Good. Really good.

The offense is averaging 32.25 points per game under Allen, compared to 20.5 under Newton. McCaffrey is playing at an NFL MVP level with three straight games of 175-plus yards from scrimmage, although he was limited to 57 by the Bucs.

The defense is playing lights-out, with 23 of their 27 sacks the past four weeks, including seven on Sunday.

And Allen? He’s completed 65.6 percent of his passes for 901 yards and seven touchdowns with no picks. That’s a passer rating of 106.6. Newton at his best in 2015 had a rating of 99.4.

If anything, this might be a good way to ease into breaking ties with the 30-year-old Newton, whose deal is up after the 2020 season. He has little trade value because of his contract and his injury history. If the Panthers let him go after the season, it would save the Panthers $19.1 in cap space in 2020, money that could go to extending the contract of McCaffrey, who is taking over as the face of the franchise. Allen currently is costing the team $495,000, maybe the best bargain in the league.

“I see the game plan they come up with each and every week. I see it through practice. I see it in the game,” safety Tre Boston said. “There is no surprise with what Kyle’s doing.

“He’s building that confidence through our team, through our guys, through his offense, through his coaches. And we have confidence in him.”

You don’t want to mess with that until you have to.