Cristiano Ronaldo is ready to return to Serie A action for Juventus against Udinese on Saturday, even as Nike and video game maker EA Sports expressed concern about the conduct of the Portuguese star, who faces a rape allegation in the United States.

The 33-year-old is the subject of a reopened investigation into an alleged rape in a Las Vegas hotel room in 2009, accusations that he has repeatedly denied.

The five-time world player of the year was seen driving into the Juventus practice complex in the morning. He has received public backing from the Italian club, which said it would not judge him on the 2009 assault claim by a Nevada woman.

Ronaldo missed the Champions League victory against Young Boys on Tuesday due to suspension and on Thursday was left out of Portugal's squad.

The show of support from the Serie A giant came shortly after Nike broke its silence in a statement that described the company's unease over its association with Ronaldo, which started in 2003. The latest terms signed in 2016 are worth a reported $1 billion, and Ronaldo has suggested that it was a deal "for life.''

"We are deeply concerned by the disturbing allegations and will continue to closely monitor the situation,'' Nike said in a statement to ESPN's Darren Rovell.

On Friday, Juventus coach Massimiliano Allegri confirmed that Ronaldo was available for selection as Juve look to continue their perfect start to the Serie A season.

"I've known Cristiano for three months now and for over 15 years of his career he has shown to be a great professional both on and off the pitch," Allegri told his prematch news conference. "He is ready to return to action tomorrow."

Beaverton, Oregon-based company Nike, however, is troubled by details emerging from a lawsuit filed last week in a Nevada state court by the accuser, who alleges she was raped by Ronaldo in Las Vegas. Police have also re-opened an investigation.

One of the wealthiest and most gifted soccer players of all time, Ronaldo wears Nike boots and appears in its advertising. The Portugal captain is also the face of the EA Sports FIFA video game franchise, appearing on the cover of the 2019 game that was released worldwide last week.

"We have seen the concerning report that details allegations against Cristiano Ronaldo,'' EA Sports told the AP. "We are closely monitoring the situation, as we expect cover athletes and ambassadors to conduct themselves in a manner that is consistent with EA's values.''

While EA Sports has not suspended the sponsorship, it has been distancing itself from the face of its game in recent days.

The company homepage still uses athletes to represent NFL, NBA, NHL, UFC and golf games. But a block of teal has replaced the spot on a banner occupied by Ronaldo until Tuesday, according to an Associated Press analysis through archived versions of the website.

Since the allegation surfaced, Juventus' share price has fallen by nearly 20 percent.

The club is listed on the stock exchange and its share price, which rose significantly when Ronaldo was signed in July, fell again on Friday by nearly 10 percent.

Also on Friday, Portugal President Marcelo Rebelo de Sousa said: "My mind has not changed at all about the role, both in sports and at a national level, that he has played in our country, even as he is facing a case in the courts. That [his accomplishments] exist and that is reality."

Whereas other players might be winding down their careers at 33, Ronaldo is still in demand by leading clubs around the world. The former Sporting Lisbon and Manchester United forward made the third big transfer of this career in July, leaving Real Madrid after nine years for Juventus, a move that cost the Italian club €112 million (then $132 million).

Ronaldo "has shown in recent months his great professionalism and dedication, which is appreciated by everyone at Juventus,'' the Italian league champions said. "The events allegedly dating back to almost 10 years ago do not change this opinion, which is shared by anyone who has come into contact with this great champion.''

Neither Ronaldo nor Juventus have addressed the allegation by Kathryn Mayorga that she received a payoff of $375,000 in 2010 after being put under pressure by the footballer's "fixers'' to keep quiet about an incident in a penthouse hotel suite.

The investment in players is so vast in soccer that clubs are reticent to enforce morality clauses by firing them. Sponsors have already stuck with Ronaldo even though he pleaded guilty in July to tax fraud in Spain and agreed to pay a fine of around $20m.

But now a well-honed reputation is facing its first serious difficulties.

Ronaldo clearly has a lot to lose. With his chiseled face and body, slicked-back hair and Hollywood film-idol looks to match his on-field talents, he has amassed 340 million social media followers to monetise that image.

He's also been an ambassador for Save the Children for five years and gained international coverage in 2016 by announcing a "generous donation'' to provide lifesaving relief to Syrians. The charity said it was "disheartened'' by the lawsuit and said it was "working to get more information'' about the rape allegation.

In June, Forbes, which has a long record of quantifying the earnings of the world's richest people, estimated that Ronaldo made an annual $108 million, with salary and winnings netting the player $61 million and endorsements a further $47 million. His haul puts him third among athletes behind now-retired boxer Floyd Mayweather and Barcelona forward Lionel Messi.

"As arguably the best footballer in the world,'' said Mark Thompson, managing director of leading sponsorship management company, SponServe, "Ronaldo is recognised the world over, offering sponsors a unique opportunity to gain maximum impact from any brand engagement.''

Ronaldo's commercial deals are not restricted to internationally recognized brands. He has been the face of Egyptian Steel , riding on horseback past the Pyramids before delivering lines to camera in Arabic.

He has also invested many of his earnings in launching and establishing his own products, notably his CR7 range, which includes hotels, shoes, underwear, fragrance and jeans, as well as a growing children's line, which he has modeled alongside his son and pushes hard on social media.

His tight embrace of social media is one reason why sponsors have been so keen to link up with Ronaldo, who has 75 million followers on Twitter, 142 million on Instagram and 122 million on Facebook.

Some companies Ronaldo promotes might appear niche, such as Japanese company MTG's SIXPAD training gear. But he is doing more than just posing in the products.

Ronaldo "is actually part of the business, and he isn't just the face of SIXPAD,'' MTG Europe General Manager Mahdiar Mazidabadi said in an email. "Therefore I am unable to make any further comments with regards to this [rape allegation] matter as it is not relevant to our business.''

Brands go to extraordinary lengths to protect their image and to be seen as good corporate citizens, and they will move fast if anything happens to dilute the value of their brands. EA, for example, was quick to drop Tiger Woods from one of the most lucrative endorsement deals in sports after he admitted to infidelity in 2013. Cyclist Lance Armstrong was ditched wholesale after he confessed to doping.

Now there are decisions to be made about Ronaldo's suitability as a marketing vehicle, and his commercial partners will be closely monitoring upcoming developments.

"What brands will be doing now is waiting and weighing up what impact any negativity will have to the brand,'' Thompson said. "They will want to protect their asset, and also any exclusivity associated to their endorsement deal, so right now, we're not likely to see any changes or knee-jerk reactions.''

Information from The Associated Press and Reuters was used in this report.