Sampdoria will protect on loan AC Milan striker
However with playing time at the Giuseppe Meazza limited, the Italian was allowed to join the Blucerchiati on loan with the possibility of co-ownership at the end of the campaign.
“Petagna is an attacker we will need,” Osti told Tele Nord.
“Milan sent him to us because he wouldn’t have had much space there and we are delighted to have netted him.
“He’s a young guy, who is very good with his head, but it is important that we don’t place too much responsibility on his shoulders.”
Petagna’s only other experience of senior football came in the latter stages of the Rossoneri’s Champions League defeat to Russian side Zenit St. Petersburg in December 2012.
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