Virgil van Dijk claims he knows nothing of interest from English clubs and is keen to prove himself in the Champions League with Celtic.
QPR loanee Tom Carroll wants to "make it at Tottenham" but is prepared to consider all of his options at the end of the season.
Motherwell have signed Faroe Islands goalkeeper Gunnar Nielsen.
The 26-year-old, who spent six months on loan at the SPL club in 2008, arrives from Danish club Silkeborg on a two-year deal.
Nielsen counts Blackburn and Manchester City among his former clubs and will challenge Lee Hollis for a first-team place at Fir Park.
He told the Motherwell website: "I'm delighted to be back and having been at some big clubs where it was hard to get a game, I can't wait to get playing again.
"I know Motherwell well from my six months here before and I know it's a great club to be at.
"I'm really pleased to get this sorted and am looking to establish myself as No 1 and do really well.
"We finished second last season and if we can do that again it would be a great achievement."