Pirlo missed the opening 1-1 draw with Paraguay and Sunday's shock 1-1 draw with New Zealand in Nelspruit with a calf injury, leaving the stuttering world champions without any real creativity in midfield.
Italy must beat Slovakia at Johannesburg's Ellis Park to guarantee a place in the last 16, although a draw will be enough if group leaders Paraguay defeat New Zealand.
Coach Marcello Lippi hopes the inventive 2006 World Cup winner can be fit for Thursday but sounded cautious.
"Today is the first time he has touched the ball in 15 days. Almost recovered? Let's see, we have to make some checks. Let's hope so but..." Lippi told a news conference on Monday back at Italy's base near Pretoria.
Pirlo would give Lippi's static midfield a bit more precision passing but he lacks pace and is not the answer to all of the Azzurri's ills.
Lippi acknowledged his side had not passed the ball as well as he would have liked against a dogged New Zealand defence but reckoned bottom-placed Slovakia would play a more open game.
"I don't believe these problems will present themselves because Slovakia have just one result to chase," he said, adding that doom and gloom was not the right approach so early in the tournament.
"You count the horses at the line. There's no crisis here, there's no crisis in the team. We don't need to talk about a crisis."
Goalkeeper Gianluigi Buffon visited the training pitch for the first time since injuring his back before last Monday's draw with Paraguay but only participated in a team meeting before heading back to the gymnasium.
His chances of facing Slovakia are almost zero with a return in the second round also looking unlikely.
