Adelaide United have been dealt a big blow heading into their AFC Champions League (ACL) opener against Gamba Osaka with defensive midfielder Isaias ruled out with a knee injury.
Isaias came off at half-time of Adelaide's 1-0 win over Newcastle Jets last week and the Reds' coach Guillermo Amor revealed on Tuesday that his compatriot will be out for at least three weeks.
Because the injury occurred less than seven days before Adelaide's first match of the ACL group stage, Amor is unable to replace Isaias in his squad for the continental competition.
The ACL operates the 3+1 quota for foreign players and Amor selected Isaias, Sergio Cirio, Kim Jae-sung and Baba Diawara in his squad for the group stage, with Marcelo Carrusca and Iacopo La Rocca missing out.
Kim replaced Isaias as the Reds' holding midfielder in the second half versus the Jets to make his Adelaide debut and appears the obvious choice to start against Gamba on Wednesday night, while other options include George Mells and Riley McGree.
Isaias' absence will hurt Adelaide two-fold.
The 30-year-old is the lynchpin of Amor's midfield - he leads the club for assists (2) alongside three others and ball recoveries (146), while he is second for tackles (54), passes (954) and chances created (21).
Adelaide will also miss Isaias' leadership with regular captain Eugene Galekovic (shoulder) out injured and Carrusca and La Rocca unavailable.
Tarek Elrich is one player who will have to take on some of that leadership and the 30-year-old defender told reporters on Tuesday that it is critical Gamba don't score early.
The J.League club have only played one competitive game so far in 2017 - a 3-0 ACL play-off triumph over Johor Darul Ta'zim on February 7 - and Elrich hopes Adelaide can take advantage of Gamba's lack of match practice.
Gamba's domestic season begins on Sunday.
"With us being fit, three quarters through our own season, we expect them to probably slow down the game," Elrich said.
"It's important not to concede early against them because we know they've got that experience to slow the game down."
Adelaide have had a tough season so far as their defence of the Hyundai A-League premiership and championship has failed to gain momentum.
But with the ACL providing something of a fresh start for the Reds, Elrich hopes he and his team-mates can build on their victory over Newcastle.
"Hopefully we can take that into this game. It adds to the confidence of the boys," he said.
"We go out there knowing that if we stick to the task, play as physical as we can, we can get a result [against Gamba]."
Adelaide and Gamba have history with the J.League outfit having smashed the Reds 5-0 over two legs in the 2008 ACL final.