The left sided defender felt a strain in his hamstring during The Reds’ last match against Central Coast Mariners.

Cassio bravely played out the game but coach Aurelio Vidmar does not want to risk any further damage to one of his star signings, especially with the team’s short turnaround to their next match against Perth Glory next Friday night.

“He’s succumbed to a hamstring injury,” Vidmar said after the team’s training session today.

“He had it last week but it wasn’t so severe and he played and was really good for us. However, the pain is over a greater area this week so we’re not going to risk it.”

Cassio has been a revelation since arriving in Adelaide in June, proving a more than capable defender while providing another avenue in attack.

Having started every game so far this season, the 27 year old is disappointed to be missing Sunday’s home game.

“It’s very upsetting to miss the game on Sunday but I am hopeful I will be back for the Perth game next Friday,” Cassio said.

With the temperature heating up to suit the A-League’s South American players, Cassio will be a loss for The Reds but with Isyan Erdogan and Tomi Milardovic along with the return of Angelo Costanzo who underwent an arthroscope on his knee, Vidmar and United will feel they have got the personnel to cover.

Adelaide has also signed MetroStars midfielder Fabian Barbiero on a short term 2 week contract. Fabian has been training with the squad for the last few months and with the current injury situation and three United players away with the Qantas Under 23’s squad, Vidmar has brought in the talented midfielder as cover.