Antonio is Lazio's lone signing so far.
Sarri said, “Marcos Antonio is a young lad, we had this opportunity to sign him – also due to rather unfortunate circumstances (in Ukraine). We had a 35-year-old player in that role whose contract was running down, so we went for this option.
“He needs to get used to Italian football, he has some Champions League experience and we're happy to give him time to adapt."
On the campaign, with a World Cup wedged in halfway, Sarri continued: “The fixture list looks difficult on paper, but often it can depend on form at that moment, so it's difficult to say. It is an anomalous situation, that's for sure, and it will be anomalous for everyone.
“We will all have to do fitness work for three months, then have a huge gap and need to start again. It doesn't seem like a good idea because of this World Cup.
“In modern football, it's impossible to start a season with a full squad in pre-season training, as there are always other tournaments going on and senior players who need more time off."