By Andrew Downie
SAO PAULO, June 30 (Reuters) - Argentina manager Alejandro Sabella paid tribute on Monday to Ezequiel Lavezzi's versatility and good-humoured presence in the squad, saying the striker would be an able deputy for Sergio Aguero if he is not fit to face Switzerland.
Sabella would not reveal any details of his team ahead of Tuesday's last-16 match in Sao Paulo but praised Lavezzi and said he gave the team different attacking options.
"In case Lavezzi plays he can play in two different positions," Sabella told reporters.
"He can play as a striker or on the right or left wing so we can use two systems with one player. But I am telling you the line-up is not decided yet."
Aguero was substituted in the 38th minute of Argentina's 3-2 win over Nigeria in their final Group F game and is doubtful to face the Swiss.
Argentina have won all three matches in the tournament but have relied heavily on Lionel Messi, who scored four of the team's six goals.
That leaves Lavezzi, who replaced Aguero in two of the three games, as the player most likely to start up front and Sabella praised his patience and group ethic.
The 29-year-old striker is known as the squad's joker and is popular with his team mates.
"Players like Lavezzi are always very positive, because they keep players happy," Sabella said. "They keep a nice atmosphere in the group. And Lavezzi is a great player.
"He has been with us since the qualifying rounds. He hasn't been in the starting line-up but still he never makes negative comments, he never makes faces, he is always supporting the team."
Sabella warned that his team will need to be at their best to beat the Swiss, and said there was no room for errors.
"The team is very well-spirited, we are all very positive, but this is a different phase and mistakes are unacceptable," Sabella said.
"In the first phase you can make a mistake you can still recover and go on, here it is much more difficult."
(Editing by Ed Osmond)