Danielli added: "I had said before that I was keen to get more playing time in as I haven't had too many games so far this season so I'm really pleased to be making the move to Scotland and hopefully will stake a claim for a place in The Borders' starting line-up."
Alastair Cranston, chief executive of The Borders, said: "Having Simon on board will develop more competition within the backs which is very healthy for the squad. The key thing is that Simon has great experience behind him, especially in defence, which we will welcome here at The Borders."
Steve Bates, head coach of The Borders: "It's great that Simon will be in Scotland and having the opportunity to play top class rugby. We're obviously very happy that he's coming to The Borders but it's merely part of the overall drive to strengthen Scottish rugby.
"Simon will be a very valuable at The Borders. He's got Premiership experience and that counts for a lot. I think that he will be a very potent attacking weapon for us."