After four seasons in North London, Jesus opted to move on from the Premier League champions, as part of a €10M exit deal from the Emirates Stadium.
The Brazil star has seen his first team opportunities blocked by Kai Havertz and Viktor Gyokeres alongside a string of injury issues.
The current LaLiga champions have taken a chance on him, following the departures of Robert Lewandowski and Ferran Torres, and Hansi Flick is ready to throw him into the action at the Estadio Mestalla.
"He's certainly not at 100% just yet, but he can already play a few minutes. He has a chance to play in the second half.
"I've really liked how he's arrived and what I've seen so far. All of which has been done without being at 100%, but he's ready to play. He's one of the options for tomorrow in the second half, depending on how the game goes."