|Date of birth||8 June 1998|
|Place of birth||Padua, Italy|
|Height||1.87 m (6 ft 1+1⁄2 in)|
|2018–2019||→ Atalanta (loan)||0||(0)|
|2019–||→ Pisa (loan)||3||(0)|
* Senior club appearances and goals counted for the domestic league only and correct as of 10 February 2020|
‡ National team caps and goals correct as of 8 September 2020
Varnier made his professional debut with Cittadella on 30 December 2016, aged 18, in a Serie B match against Virtus Entella. He obtained 14 league appearances on his first professional season. On 25 November 2017 he scored his career's first goal in the league match won 2–1 against Salernitana.
On 2 July 2018, he joined Serie A club Atalanta on a season-long loan with Atalanta holding an obligation to buy his rights at the end of the 2018–19 season. During his second training with Atalanta, Varnier suffered anterior cruciate ligament injury in his right knee and was unable to make any appearances in his first season.
- "Game Report by Soccerway". Soccerway. 30 December 2016.
- "LA FIRMA SUL CONTRATTO NELLA SALA RIUNIONI PRESIDENZIALE DEL CENTRO BORTOLOTTI" (in Italian). Atalanta. 2 July 2018. Archived from the original on 29 October 2018. Retrieved 28 October 2018.
- "IL PISA INGAGGIA IL DIFENSORE MARCO VARNIER" (in Italian). Pisa. 27 August 2019.