On 6 July 2018, he joined Serie B club Salernitana on a season-long loan. Salernitana held an option to buy him out at the end of the season, which would turn into an obligation to buy if Salernitana got promoted into Serie A.[3]
After making only five appearances for Salernitana in the first half of the season, he was recalled from loan. On 25 January 2019, he rejoined Ternana on another loan until the end of 2018–19 season.[4] On 3 August 2019, he returned on loan at Ternana until 30 June 2020 with an option to buy.[5] Upon his return from this loan, he made his Serie A debut for Sampdoria on 2 October 2020 in a game against Fiorentina, he substituted Albin Ekdal in the 84th minute of a 2–1 away victory.[6] On 5 October 2020, he returned to Ternana for his third loan.[7] On 15 June 2021, Ternana exercised their option to purchase his rights and he signed a four-year contract with the club.[8]
On 13 November Mazzitelli was returned from injury, but Alberigo Evani the coach still kept Palumbo in the squad, as well as adding Leonardo Capezzi to the call-up.[13] On 17 November Palumbo was featured as a bench warmer again.