ANKARA

The UEFA Europa League's knockout playoffs round will begin Thursday with a highly-anticipated match between Spain's Barcelona and English club Manchester United.

Barcelona were among eight UEFA Champions League clubs who finished third in each of their groups in November.

Manchester United came second in the Europa League Group E after Spain's Real Sociedad directly qualified for the Round of 16.

The knockout round is a stage before the last 16.

Barcelona captain and longtime defensive midfielder Sergio Busquets suffered an ankle injury and will miss the Villarreal match Sunday.

Barcelona product Busquets, 34, played against Manchester United in the 2009 and 2011 UEFA Champions League finals where Barcelona won both titles in Rome and London.

Barcelona’s French forward Ousmane Dembele sustained a hamstring injury last month and is ineligible for the club's last three matches against Real Betis, Sevilla, and Villarreal in February.

Manchester United are troubled by suspended and injured players before the showdown Thursday with Barcelona at Spotify Camp Nou Stadium.

Lisandro Martinez, Manchester United's Argentine defender, is suspended for the first leg.

Austrian midfielder Marcel Sabitzer, who joined Man Utd from Bayern Munich in January, was booked three times for the German club in the Champions League group phase and will miss the match against Barcelona.

Other Manchester United midfielders Christian Eriksen and Donny van de Beek will be out for some time with major injuries.

Scott McTominay, Man Utd's Scottish midfielder, did not play in last week's Leeds United matches in the English Premier League due to an injury.

McTominay is expected to be sidelined against Barcelona.

The Europa League playoff matches will be played in two legs where they will end Feb. 23.

The eight winners will join eight group winners in the last 16 draw next Friday. The losing eight teams will be eliminated from the European competition.

The showdown between Barcelona and Man Utd, which will be refereed by Italy's Maurizio Mariani, will start at 1745GMT in Barcelona.

In the second leg, Barcelona will visit Manchester United on Feb. 23, one day before the last 16 draw.

Thursday's fixtures:

Barcelona - Manchester United

Shakhtar Donetsk - Rennes

Ajax - Union Berlin

Salzburg - Roma

Juventus - Nantes

Sporting - Midtjylland

Bayer Leverkusen - Monaco

Sevilla - PSV Eindhoven