NFL heads into 2015 with popularity intact — but there are issues

The nation’s most popular sports league put that fan loyalty to the test this season.

Amid the domestic-abuse scandals involving star running backs Ray Rice and Adrian Peterson, the NFL lurched through the most turbulent fall in its 94-year history.

There are all sorts of questions about how the league will handle player discipline and navigate its acrimonious relationship with the players’ union.

On the field, the NFL is as successful as ever, with new stars emerging, including this season’s crop of phenomenally talented rookie receivers: Odell Beckham Jr. of the New York Giants, Carolina’s Kelvin Benjamin, Buffalo’s Sammy Watkins and Tampa Bay’s Mike Evans.

There’s the familiar success of Coach Bill Belichick in New England, and the electrifying rise of the onetime Patriots coach he replaced, Pete Carroll of the Seattle Seahawks.

There’s the pinpoint accuracy of quarterback Aaron Rodgers in Green Bay; the poise of Seattle’s Russell Wilson, who is so calm under pressure it’s as if he can stop time; the all-around excellence of Andrew Luck in Indianapolis; and a couple of legends in Peyton Manning and Tom Brady who can pass all day but refuse to pass the torch.

Among the questions going forward:

Can the NFL and the players union find a happy medium when it comes to punishments?

The acrimony between the league and the NFL Players Assn. has reached a full boil, and Commissioner Roger Goodell’s modified personal conduct policy hasn’t turned down the heat. Although Goodell has stepped away from the first stage of player punishment, he has retained control of the appeals process. The union argues that should be handled by a neutral third party. This figures to be an issue that will bubble to the surface in every high-profile punishment case.

Have the Browns seen enough of Johnny Manziel to know what they have?

So far, Johnny Football has been Johnny Crash. The diminutive rookie quarterback’s something-out-of-nothing style has been a flop in his first two starts, and he lasted only three full possessions at Carolina before being sidelined by an injury. Cleveland needs to figure out its future at the position because Brian Hoyer becomes a free agent after the season, and he doesn’t want to ride the bench.

Is there a future for Robert Griffin III in Washington?

The Redskins are feeling better about their quarterback after his solid performance against Philadelphia on Saturday, but those sentiments seem to change from week to week. The tension has been thick this season between RGIII and first-year Coach Jay Gruden. The primary reason the team hired Gruden was to bring out the best in the quarterback, but that relationship is already on shaky ground.

How long will the window of opportunity stay open for Peyton Manning and Tom Brady?

Denver’s Manning, 38, is focused on short-range goals. “Our strength coach, Luke Richesson, I feel like he’s really set out a good plan for me,” Manning told The Times in August. “He kind of jokes that he has this five-year plan for me. I say, ‘No, I’m on the 2014 plan. Let’s hone in on that.’”

New England’s Brady, 37, has a different approach. He recently told Sports Illustrated he wants to keep playing into his 40s and his throwing coach Tom House told the magazine: “Tom is pushing back the aging process. There’s no reason he can’t do at 45 what he did at 25.”

What will the demand be next season for running backs Adrian Peterson and Ray Rice?

Rice’s domestic-abuse suspension was lifted on appeal in November, and teams have been eligible to sign him since then. He’s unlikely to generate much demand, not only because of the stigma he carries, but also because he’ll be 28 in January and his numbers were on the decline before he got into trouble. Peterson, suspended until at least April 15 after pleading no contest to striking his 4-year-old son with a switch, will wind up playing somewhere, though it might not be with the Minnesota Vikings. Age is a factor with him too — he turns 30 in March — but to this point he’s been a once-in-a-generation back.

Will Dallas’ quarterback ever get off the Romo-coaster?

The end of this season will be a good indicator if Tony Romo, 34, has more than warning-track power. The up-and-down quarterback has a rock-solid offensive line, the league’s leading rusher in DeMarco Murray, and a dominant receiver in Dez Bryant. The Cowboys are back in the playoffs for the first time since 2009, and now’s the time Romo can prove he’s capable of getting the job done.

What happens to Jim Harbaugh?

He led San Francisco to three consecutive NFC championship games and one Super Bowl, but Harbaugh and the 49ers are likely to part ways at the end of the season. The University of Michigan, Harbaugh’s alma mater, reportedly has offered him a six-year deal worth $48 million. Can he pass on that? Might he move across the bay to coach the Oakland Raiders, for whom he once was an assistant coach? It’s highly unlikely the notoriously cheap Raiders can match that Michigan money, but they’re badly in need of someone to rebrand the foundering franchise. Plus, it would be a poke in the eye of their NFL neighbors.

If the Jets give their coach the boot, where will Rex Ryan wind up next?

Yes, his team made the conference championship his first two seasons and then things got progressively worse, but Ryan shouldn’t have a problem landing a head-coaching job elsewhere in the league. He had success early with the Jets, and he’s got a colorful personality that will be attractive to some clubs. Oakland could be a fit, or maybe Atlanta if the Falcons get rid of Mike Smith (although they have a chance to salvage their season by winning the division). Hard to imagine Ryan in San Francisco. Maybe he goes back to Chicago, where his dad, Buddy, had so much success as Bears defensive coordinator.

Who’s the next college coach to follow in the footsteps of Pete Carroll, Harbaugh and Chip Kelly, and find success in the NFL?

There’s speculation that Baylor’s Art Briles might make the jump up at some point, or maybe Stanford’s David Shaw. And what about the coach Carroll replaced in Seattle? Does UCLA’s Jim Mora feel the pull of the league he left? There are murmurs that the 49ers could be eyeing Mora, their onetime defensive coordinator, and that could put him back in the Seahawks’ division to go head-to-head with Carroll twice a season.

What happens with the quarterbacks at the top of the upcoming draft?

‘Tis the season for teams to fall in — or out of — love with quarterback prospects. Will Oregon’s Marcus Mariota go No. 1 overall, even though the market has cooled on run-pass threats such as Colin Kaepernick, Cam Newton and RGIII? (Russell Wilson’s stock keeps climbing, though.) Will Florida State’s Jameis Winston slip in the draft amid character questions, or will the player who has never lost a college football game convince NFL teams that he’s the best prospect in this draft class? The Winston question figures to be the hottest topic at the scouting combine. And what happens with UCLA’s Brett Hundley?

What can the league do to make Thursday night games more competitive?

Blowouts were the norm in midweek games, particularly early in the season. Many of the highly anticipated matchups were downright unwatchable. The league needs to consider scheduling Thursday games only in the immediate aftermath of the participants’ week off.

Now that the Chargers, Rams and Raiders are staying put in their cities for at least another year, how does the league maintain momentum in the Los Angeles market?

Watch for the NFL to zero in on a specific stadium site, whether it’s the Farmers Field proposal downtown, the Hollywood Park area, Carson or somewhere else. You can expect the league to turn its attention to a venue concept, and come up with financing alternatives, and then wait to determine which team or teams might relocate — if that ever happens.

Follow Sam Farmer on Twitter @LATimesfarmer