The Men in Black have been nomadic hosts this season, playing their home games at a variety of locations while they wait to play at their new stadium at Allianz Park in Barnet in February.
Saracens have been based at Vicarage Road since 1997, sharing the ground with Watford FC, but the two clubs agreed to part ways in 2010 and this will be the first time the Men in Black have played at the football ground this campaign.
Gustard said: “I think this is our eleventh different venue we’ve played in since the start of the season so it’s been an unbelievable journey – we’ve seen the sites and to play at the likes of Wembley, Twickenham and Brussels has been great.
“We’ve obviously had an affiliation with Vicarage Road over the years and it’s nice, it’s another part of our journey until we get to our real home at Allianz Park.
“It’ll also be good for some of the supporters who haven’t been able to take advantage of some the brilliant trips we’ve been on and to see the club and see the side they support in action at our spiritual home, even if it isn’t our actual home anymore.”
Kick-off on Sunday is at 2pm.