Australian attackers Andrew Nabbout and Tomi Juric have both missed their respective clubs' past five games due to minor injuries.
The duo were named in Bert van Marwijk's preliminary 26-man Socceroos World Cup squad last week and will link up with the squad in a European camp.
They are however struggling for full fitness with a shoulder injury sidelining Nabbout for Japanese side Urawa Reds while a back complaint has kept Juric out of the action for Swiss club Luzern.
Nabbout's last game came on May 2 against Kawasaki Frontale with the 25-year-old replaced after 75 minutes.
The former Newcastle Jet earned a transfer to Japan midway through the A-League season but has made just six appearances and one start for the Reds.
He was however heavily involved in Bert van Marwijk's first two games in charge back in March and was utilised as both a winger and striker.
Juric's last glimpse of match minutes was nearly a month ago on April 23 in a 2-1 win over Zurich with the former Western Sydney Wanderer replaced after 68 minutes.
The 26-year-old striker has made 27 league appearances for Luzern this season scoring seven times with the club sitting third.
Both will no doubt be desperate to shrug off these injuries and show what they can do ahead of a crunch friendly on June 1 against Czech Republic which will see three players cut from the squad in the days after.