Josip Ilicic returned to Atalanta on Monday after nearly two months away from the Serie A team for unspecified personal reasons, Italian media reported.
Slovene Ilicic, 32, didn't finish the last Serie A campaign following its post-lockdown restart, and returned to his home country in July.
The forward, a key player in a team that scored nearly 100 goals in Serie A last season, also missed his team's Champions League quarter-final with Paris Saint-Germain, lost 2-1 thanks to two last-gasp goals from the French champions.