But Pienaar has instead opted to remain at Ravenhill for a further three years as Mark Anscombe's men look to build on their 2012 Heineken Cup Final showing and last season's runners up spot in the RaboDirect PRO12.
"To be successful, you need top-class players, therefore I am extremely pleased that Ruan, who is one of the best scrum-halves anywhere in the world, is extending his time with us," said Ulster's director of rugby, David Humphreys, after Pienaar agreed a contract extension that will see him stay put until at least the summer of 2017.
"The announcement of this contract will give everyone at Ulster Rugby - the players, the staff and the fans - a huge lift, especially as it had been wrongly reported that Ruan would be leaving us.
"It was no surprise to us that his services were coveted by other clubs, but we always knew that what we could offer him in terms of a great playing squad, a world-class stadium and state-of-the-art training facilities would be enough to make him want to stay.
"Ruan's decision to commit to three more years at Ravenhill is a huge endorsement of what we are doing at Ulster and I have no doubt that he will be a key part of our success in the coming seasons."
Pienaar has been a central figure in Ulster's European progress in recent years, with his arrival in the 2010/11 campaign coinciding with a first quarter-final showing since their Heineken Cup winning heyday of 1999.
The 29-year-old has scored more than a half century of points in 63 appearances for the Irish outfit, with exactly a third of those games coming in Europe's premier club competition.
He featured in all seven of his side's Heineken Cup matches last season and scored 80 points in the same number of games the year before as Ulster made it all the way to the final before being beaten by Leinster in the tournament showpiece at Twickenham.
Equally adept at fly-half, Pienaar has 71 international caps to his name and was heavily involved in his country's recent Rugby Championship fixtures with New Zealand, Argentina and Australia.
He returned to Northern Ireland on Monday and is line to make his first Ulster appearance of the season when they kick off their Heineken Cup challenge at home to former winners Leicester Tigers on Friday night.