Superbowl Sunday is the biggest day in US sports.

The New England Patriots will play the Seattle Seahawks for the National Football League (NFL) championship in Phoenix, Arizona. An estimated 115 million people will watch the game on TV.

But it's been a rough season for the NFL, which has been plagued by scandals, criminal cases and suspected cheating.

The problems started well before the current season began.

In February, Baltimore Ravens player Ray Rice was caught on tape punching his then-fiancee Janay Palmer unconscious in a hotel lift.

When the knockout went public, the league's commissioner Roger Goodell gave Rice a two-game unpaid suspension - widely seen as a slap on the wrist and an insult to victims of domestic violence.

When more damning video emerged, Goodell hastily backtracked, suspended Rice indefinitely and announced a strict anti-domestic violence policy.

The assault case against Rice never went to trial. The Ravens dismissed him but he's still eligible to play if signed by another team.

In September, Minnesota Vikings star player Adrian Peterson was charged with child abuse in Texas after he beat his four-year-old son with a tree branch, causing bruises and bleeding.

He pleaded no contest to assault and avoided jail time. At first, the Vikings suspended Peterson for just one game, but later the league removed him for the season.

The scandals, together with longstanding concerns over the effect of concussions suffered on the field, have taken a toll on public opinion.

'PR disaster'

Tom Bernthal, the chief executive of the Los Angeles branding strategies firm Kelton, says the NFL's public relation efforts have been "a disaster".

"It's not what you do, it's what people perceive that you are doing," he says.

"The perception, the public opinion around what the NFL did, is that they ran from it, they hid from it. They tried to cover it up. They tried to belittle it and if that is the perception, that is the reality.”

As the season entered its final days a new scandal emerged: 'Deflategate.'

Officials discovered that footballs used by the New England Patriots in their victory over the Indianapolis Colts on the way to the final were deflated to below the league standard.

Less inflated footballs are easier to handle and throw. Now many fans wonder whether the Patriots cheated their way into the Superbowl.

Patriots' coach Bill Belichick and quarterback Tom Brady have denied any illicit ball handling and said they were shocked by the whole thing.

The league is investigating, but the results won't be known for weeks - well after the Superbowl has been won.

Despite the season being widely viewed as a public relations flop, professional football is still the most popular sport in the US.

As millions gather to watch the Superbowl on Sunday, its broadcaster is charging advertisers $4.5m for 60 seconds of airtime.

Source: Al Jazeera