The Korea Football Association (KFA) said Koo has been diagnosed with acute pyelonephritis. The FC Augsburg midfielder is also expected to miss German Bundesliga matches.

Koo, who has 19 goals in 70 matches, was looking to make his first appearance since Paulo Bento took over as head coach in August. He didn't play in Korea Republic's friendly matches against Costa Rica and Chile last month.

Arnold’s squad selections for October’s FIFA window includes 21-players that featured in the Socceroos’ recent training camp in Turkey, and also marks the returns of attacking weapons Mathew Leckie and Tom Rogic to the squad for the first time since the 2018 FIFA World Cup in Russia.

The squad that will convene in the UAE from Monday features four players yet to make their senior international debuts – youngsters Thomas Deng (21), Denis Genreau (19), and Awer Mabil (23) – as well as 25-year-old attacker Martin Boyle. While Deng, Genreau, and Mabil will each be aiming to achieve maiden match minutes for the Socceroos in Kuwait City, Boyle will travel with the squad for the UAE leg of the camp only.

You cast well over a million votes for your best-ever AFC Asian Cup forward, and now it's time to turn our attention to midfielders.

So, here are 10 candidates for the spots at the middle of the park. Review the nominees and then choose your favourite midfielders to set the tempo for this all-star XI in the poll below.

Iran won the last of their titles in 1976 and Quieroz said this is a wait that must end.

“My responsibility as a coach is to lead my team to our target. Our biggest challenge in the UAE is winning the title. We’ve not won the title since 1976,” the former Real Madrid coach said to the Football Federation Islamic Republic of Iran website.

Iran are in Group D alongside Iraq, Vietnam and Yemen and their first target will be to navigate into the knockout stage in UAE 2019 on January 5-February 1.

The ceremony was held in conjunction with a two-day Teams' Workshop currently taking place in the UAE, which aims to equip all 24 participating teams with the necessary tools to ensure a successful tournament through a series of sessions for team managers, doctors and officials, covering essential matters such as sports integrity, refereeing, media, team services as well as medical information, among others.

After approval from FIFA and the International Football Association Board (IFAB) and consultation with the AFC Competitions and Referees Departments, the AFC Executive Committee approved the implementation of VAR at the AFC Asian Cup UAE 2019 – pending final confirmation that all necessary preparation is in place.

Shaikh Salman bin Ebrahim Al Khalifa, the AFC President, said: “Asian football is determined to embrace technology for the good of the game and we are looking into the introduction of VAR at some stage during the AFC’s pinnacle competition – the AFC Asian Cup in the United Arab Emirates.

“We saw the VAR first hand during the 2018 FIFA World Cup in Russia and it was clear to everyone that there needed to be a great deal of training of officials and investment in facilities to make sure that the system was effective and a positive addition to the game.

Australia, who had relinquished the top spot to IR Iran in the August rankings, remain as Asia's second best team at 43rd while Japan moved up one spot to 54th.

Korea Republic improved to 55th, up two places and are the continent's fourth best ranked team.

Saudi Arabia complete Asia's top five, moving down one spot to 71st.