PERTH, Australia -- Spain's Tommy Robredo has an arm injury and has withdrawn from the Hopman mixed teams tournament which begins Saturday.

Tournament officials did not give any additional details Friday on the injury, saying No. 18 Robredo would be replaced by 194th-ranked Daniel Munoz-De La Nava.

Poland's Jerzy Janowicz withdrew with a foot injury a week ago and was replaced by Grzegorz Panfil, who will team with Agnieszka Radwanska.

Australia, represented by Bernard Tomic and Sam Stosur, will begin play Saturday against Canada's Milos Raonic and Eugenie Bouchard at Perth Arena. Poland plays Italy in the other Group A match.

The United States, represented by Sloane Stephens and John Isner, is playing in Group B with France, Spain and Czech Republic. The winners of each group play in the Jan. 4 final.