The Juventus defender received emergency cortisone treatment for an insect bite on August 28 and then failed a dope test after a Serie A match two days later, the club said on Thursday.
Cannavaro had requested an exemption after being treated for the bite but did not receive it before he was tested.
"I haven't heard from Fabio, there was no need. Everything was cleared up in two hours," Lippi told reporters.
He was already suspended for Italy's World Cup qualifier in Ireland on Saturday, when a point will put the world champions through to next year's finals, but is due to meet up with the squad on Sunday ahead of Wednesday's home game with Cyprus.
"Definitely yes," Lippi said when asked if the 36-year-old would join the Azzurri on Sunday.
Media reports said Cannavaro was spotted meeting the Italian Olympic Committee's (CONI) anti-doping chief Ettore Torri in Turin late on Thursday and that a judgment may come on Friday.
Cannavaro should escape a doping ban but Juve could be fined, the reports added.
"It would be awful to make this out as a doping case when it isn't," Juve and Italy team mate Giorgio Chiellini told reporters. "I was there when Fabio was stung by the wasp. His arm swelled up straight away. He is calm and so are we."
Torri has been relentless in his battle against doping and has charged sports personalities even when they have argued that their positive tests were the result of accidents.
Cyclist Alessandro Petacchi failed a drugs test for salbutamol and despite arguing that the results were because he had overused his asthma inhaler, Torri still banned him for a year and the Court of Arbitration for Sport (CAS) agreed.
Cannavaro was famously videoed inserting a drip into his arm on the eve of a 3-0 victory over Olympique Marseille in the 1999 UEFA Cup final when playing for Parma.
His lawyer confirmed the drip contained Neoton, a drug used in cardiac surgery to protect the heart, and was not on the World Anti-Doping Agency's list of banned substances.
