The striker had started the match in Turin on Tuesday evening, but was forced off in the opening stages after a crunching Fabio Gatti sliding tackle.
He landed awkwardly and had to be substituted by Gustav Isaksen in the 2-0 defeat to Juventus.
“Zaccagni suffered a bad ankle sprain,” confirmed coach Igor Tudor in his press conference.
Chief Lazio medic doctor Fabio Roda provided more details to Lazio Style Channel.
“Zaccagni sustained a serious sprain to the left ankle, so he will have more tests for a more accurate diagnosis and prognosis in Rome.”
It is another blow for the Italy international, who already had to miss 20 games this season, including an ankle sprain in October 2023.
There were also updates on some of the other Lazio players going into this weekend’s Derby della Capitale against their arch-rivals Roma.
“Patric had just returned from a long lay-off, so was a little short on energy and it was decided to substitute him at half-time, but there was no medical issue.
“Manuel Lazzari has a low-grade lesion to the left calf. He has already started physiotherapy, tomorrow we will repeat the tests to have a more accurate idea of when he can return to the field.”
The Biancocelesti are also going to be without goalkeeper Ivan Provedel, while midfielder Nicolò Rovella is a major doubt too after his long lay-off.
The positive news should be the return of Luca Pellegrini, who was suspended for both Serie A and Coppa Italia clashes with Juventus.
