River coach Diego Simeone dropped the 34-year-old former Argentina international from the first team last week as he undergoes further treatment for an alcohol addiction, and he has since been loaned to second division side Independiente Rivadavia.

And Robert Flores, who arrived at the Estadio Monumental on a one-year loan from Villarreal, is ready to fill Ortega's boots when River travel to Colon on Sunday.

"It will not be easy because of what Ortega means in this club and how fans love him. I hope I can play on Sunday," said Flores.

"I promise the fans that I will do my best for River. Being here is a dream come true."

Paraguayan striker Santiago Salcedo, who arrived this week from Newell's Old Boys, is dreaming about helping Los Millonarios retain the title.

He said: "I came here to be a champion. I am anxiously waiting to wear the River shirt."

River's arch rivals Boca Juniors, the Clausura runners-up, will prioritise the domestic league over the continental Copa Sudamericana this term.

Carlos Ischia - whose team's last title was the 2006 Clausura - wants his troops to be as fit as possible for their home game against Gimnasia y Esgrima Jujuy on Sunday.

"Our priority this term is the league," he said. "Then, we will start thinking of the Sudamericana, but it's been a long time since Boca last won the league."

Juan Sebastian Veron could miss Estudiantes' opener at Rosario Central on Saturday after picking up a minor muscular injury on Tuesday during a Copa Sudamericana first-round match against Independiente.

Club doctor Raul Zamponi revealed the former Chelsea and Manchester United midfielder sustained a "not serious contraction to his left leg" and would be tested again to ascertain the severity.

He added: "If this spasm continues, we will be unable to count on him for a while in the future."

Miguel Angel Russo, who guided Boca Juniors to the 2007 Copa Libertadores title, will oversee his first domestic match at San Lorenzo on Sunday against Tigre.

And Russo - the successor to Ramon Diaz who moved to Mexican giants America - will do so without two of last season's most important players with former Argentina internationals Andres D'Alessandro and Diego Placente transferred to Internacional of Brazil and French side Bordeaux respectively.

Tucuman-based San Martin return to top-flight action after 16 years at home to Huracan in the Apertura's opening game on Friday.

The other promoted side, Godoy Cruz, are back after one year in the Nacional B tournament and travel to Banfield on Saturday.

Fernando Gamboa will make his coaching debut as Newell's Old Boys visit Gimnasia y Esgrima La Plata on Friday.

Arsenal, who recently lifted the Suruga Bank Cup in Japan, challenge Argentinos Juniors, while Velez Sarsfield clash with Independiente at the Estadio Jose Amalfitani. Both games will be played on Saturday.

Finally, giants Racing Club, who avoided relegation by winning a play-off against second division side Belgrano, host Lanus on Sunday.