The 18-year-old was handed his Serie A debut by Massimiliano Allegri during Milan's opening-day defeat to Verona, but has now been sent out to continue his development.
And Petagna has revealed that the advice of two of his Milan team-mates helped him make the decision to move to the Stadio Luigi Ferraris.
"I spoke with (Antonio) Nocerino and (Giampaolo) Pazzini," he told TMW. "They both advised me to choose Sampdoria.
"They spoke well of boss Delio Rossi and I'm really happy. Now I want to feature as much as I can with the Doria jersey."
Petagna has been capped by Italy at every age level up to Under-19.
The Trieste-born forward made his first professional outing as a 17-year-old, coming on during a UEFA Champions League clash with Zenit St Petersburg.
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