Sigurdsson is on-loan at Swansea from Hoffenheim and available for £10 million.
Sir Alex Ferguson, Mike Phelan and Rene Meulensteen all watched the Iceland international on Saturday against Wolves.
Tribal Football Staff are dedicated to the football tribes from all over the world. Our team is passionate about delivering football news to our hundreds of thousands of followers in all the corners of the globe. Football is life, It never stops, Neither do we.