The newly-promoted club are embarking on their first ever Serie A campaign after winning the promotion play-offs in June.
They have been remarkably active on the transfer market, bringing in over a dozen new players.
The latest addition is Pablo Mari, who signed on loan with an option to buy for €5m.
That will become an obligation if Monza avoid relegation and confirm their Serie A status for next season.
A similar deal is in place for Napoli striker Petagna, who is expected to undergo his medical tomorrow morning, as he is already travelling towards Monza this evening.
That loan will cost circa €2.5m with another €10m to make it permanent, plus bonuses.