Valzania started his career at Cesena. On 13 May 2014 he made his professional debut for Cesena in Serie B as a substitute replacing Moro Alhassan in the 76th minute of a 1–0 home win over Empoli. At the end of 2013–14 season Cesena won the Serie B play-off and it was promoted in Serie A. On 6 January 2015, Valzania made his Serie A debut in a 4–1 home defeat against Napoli, he was replaced by Massimo Volta in the 79th minute.
Atalanta
On 30 June 2015, Valzania was sold to Atalanta B.C. for €6 million. That transfer window Cesena also signed Moussa Koné and Federico Varano from Atalanta, for a total transfer fee of €6 million.
Loan to Cesena
On 2 July 2015, Valzania was loaned back to Cesena on a season-long loan deal. On 9 August, Valzania made his debut for Cesena in a 4–0 home win over Lecce in the second round of Coppa Italia, he played the entire match. On 5 September he made his Serie B debut for Cesena in a 2–0 home win over Brescia, he was replaced by Luca Garritano in the 63rd minute. On 19 September he played his first entire match for Cesena, a 3–1 away win over Ascoli. On 1 December he played in the fourth round of Coppa Italia, a 4–1 away defeat against Torino. Valzania ended his loan to Cesena with 19 appearances and 1 assist.
On 15 July 2016, Valzania was loaned to Serie B club Cittadella on a season-long loan deal. On 7 August he made his debut for Cittadella as a substitute replacing Lucas Chiaretti in the 79th minute of a 2–1 home defeat, after extra-time, against Cremonese in the second round of Coppa Italia. On 27 August, Valzania made his Serie B debut for Cittadella in a 2–1 away win over Bari, he was replaced by Andrea Schenetti in the 77th minute. On 1 January 2017, Valzania played his first entire match for Cittadella, a 2–0 away win over Trapani. On 22 April he scored his first professional goal in the 66th minute of a 4–1 home win over Carpi. Valzania ended his season-long loan to Cittadella with 35 appearances, 1 goal and 5 assists.
On 15 July 2017, Valzania left for Pescara on a season-long loan deal, with an option to buy at the end of season. On 12 August he made his debut for Pescara as a substitute replacing Christian Capone in the 59th minute of a 3–1 away win over Brescia in the third round of Coppa Italia. On 3 September, Valzania made his Serie B debut for Pescara as a substitute replacing Mamadou Coulibaly in the 65th minute of a 4–2 away defeat against Perugia. On 19 September he played his first entire match for Pescara, a 2–2 home draw against Virtus Entella. On 2 December, Valzania scored twice in a 3–3 home draw against Ternana. On 8 December he was send off with a red card in the 90th minute of a 4–2 away defeat against Cesena. On 28 December, Valzania scored his third goal in the 86th minute of a 1–0 home win over Venezia. Valzania ended his loan to Pescara with 34 appearances, 5 goals and 4 assists.
On 8 January 2019, Valzania joined on loan to Frosinone until 30 June 2019. On 4 February he made his debut for the club in Serie A in a 1–0 home defeat against Lazio, he was replaced by Marcello Trotta after 81 minutes. On 17 March, Valzania scored his first goal for Frosinone, as a substitute, in the 70th minute of a 2–1 away defeat against Empoli. Two weeks later, on 31 March he played his first entire match for the club, a 1–0 home defeat against SPAL. Three days later, on 3 April, he scored his second goal in the 47th minute of a 3–2 home win over Parma. Valzania ended his season-long loan to Frosinone with 13 appearances, 2 goals and 1 assist, however Frosinone was relegated in Serie B.
Loan to Cremonese
On 31 August 2019, Valzania joined to Serie B side Cremonese on a season-long loan. On 15 September he made his debut for the club in a 4–1 away defeat against Pisa, he played the entire match.
