Cristiano Ronaldo was diagnosed with a viral infection on Sunday and will miss Al Nassr's Asian Champions League opener against Iraq's Al Shorta this week. The Portuguese veteran aims to add Asia's top club title to his extensive list of accomplishments as the competition commences on Monday.

"Al Nassr captain Cristiano Ronaldo was not feeling well today and was diagnosed with a viral infection," the club stated on social media platform X on Sunday. "The team's doctor confirmed he needs to rest and stay at home. Consequently, he will not be traveling with the team to Iraq today. We wish our captain a speedy recovery."

Ronaldo's first attempt with Saudi side Al Nassr ended in a quarter-final penalty shootout defeat to eventual champions Al Ain earlier this year. Now rebranded as the Asian Champions League Elite, Al Nassr and other Saudi teams are poised to be major contenders after significant investments in players like Ronaldo and Neymar over the past two years.

England forward Ivan Toney recently joined Al Ahli from Brentford for over $45 million, marking another high-profile move to Saudi Arabia. The new-look competition will feature a mini knockout tournament from the quarter-finals onwards, hosted by Saudi Arabia, which is expected to stage the 2034 World Cup. The champions will receive at least $12 million.

Al Nassr, Al Ahli, and Neymar's Al Hilal will participate in the Champions League Elite's launch on Monday, with a new format dividing 24 teams into two groups of East and West. Each team will face eight different opponents in the group stage. The top eight teams from each zone will compete in the last 16 over two legs in March, leading to the final stages in Saudi Arabia from April 25 to May 4.

Saudi champions Al Hilal aim to extend their record with a fifth Asian title but await the return of Brazilian star Neymar, who has been sidelined since a serious knee injury last year. Al Hilal has bolstered their squad with the signing of Portugal full-back Joao Cancelo from Manchester City, joining Aleksandar Mitrovic, Sergej Milinkovic-Savic, and Ruben Neves.

Despite Ronaldo's absence for Monday's opening match in Baghdad, Al Hilal can still rely on Sadio Mane, Aymeric Laporte, and Marcelo Brozovic. Defending champions Al Ain, from the United Arab Emirates, were coached by Argentina great Hernan Crespo to victory against Japan's Yokohama F-Marinos in May's final.

Al Ain is one of two UAE clubs participating in this year's edition, with teams from Qatar, Iran, Uzbekistan, and Iraq completing the West zone lineup. In the East, Japanese clubs have historically performed well, with Yokohama returning to lead their challenge. Coach Harry Kewell was dismissed after guiding them to last season's final, due to the team's poor domestic form.

Kawasaki Frontale and Vissel Kobe also represent Japan, while South Korea's Pohang Steelers, Ulsan, and debutants Gwangju carry their nation's hopes. Chinese clubs' spending power has diminished, but former Chelsea attacker Oscar remains with Shanghai Port, led by Australian coach Kevin Muscat. Shandong Taishan and Shanghai Shenhua are also involved from China, with one club each from Australia, Thailand, and Malaysia participating in the East league stage.