Juan Pablo Socino has joined Saracens on a one-year contract.
The 32-year-old back has four Argentina caps and extensive experience of playing club rugby in England.
Most recently at Club de Rugby El Salvador in Spain, he can play at fly-half or centre.
Saracens will be in the Championship for the 2020/21 campaign, having been relegated for salary cap breaches.
Saracens director of rugby Mark McCall told the club website: "Juan Pablo is a hugely experienced player and will have a significant role to play in the exciting challenge ahead.
"We have been impressed with his desire and motivation to make the most of this opportunity, and have no doubt he will have a positive influence on some of our younger players."
Socino has played over 100 games in the Championship for Rotherham Titans and Nottingham Rugby.
He has also spent time in the Premiership with Newcastle Falcons.
"I was in Spain so, for an opportunity to come like this, it was huge," said Socino.
"I've played against Sarries a lot and I know what they mean in English rugby. I know what they've achieved, I know what they've done.
"To be joining such as a successful club is huge for me and my family."