Messi a doubt for Argentina ahead of Copa quarter-final
Messi missed Argentina's final group stage match on Saturday, a 2-0 win over Peru, after complaining of a sore right hamstring.
Argentina will hold a training session later on Wednesday and Scaloni said he would make any decision afterwards.
"We'll wait a couple of hours and make the decision. It is always better to have one more day," he told a press conference.
"Yesterday we had good feelings and we'll take this day to define the team based on the response we get today," he added.
Scaloni said he would consult with Messi about his readiness for the game.
"We'll try to get him in and then, if he's not (ready), we'll look for the best solution for the team. I'll talk to him today. I think it's fair that he takes his time and trains as much as possible," he said.
