Reports in Italy claim the Premier League giants are lining up a £26million bid to sign the Chile winger.
Sanchez has been linked with a move away from Udine in the winter transfer market with several clubs, including Inter Milan, keen to acquire the 22-year-old's services.
Highly rated: Alexis Sanchez (right) is attracting interest from Inter and Chelsea
Hotshot: Winger Sanchez (centre) has scored five goals in 19 league games this season
'I know Udinese is a serious club,' said Guidolin to Italian TV station Rai Due. 'The club have reiterated that Sanchez will remain at Udinese until the end of the season and I have no doubts on this matter.
'Of course, if a tempting offer would arrive it would be right for the club to evaluate it but I believe that Alexis can still grow from here on until the end of the season if he stayed with us.
'After that, he is destined, considering the quality he has shown for some time, to join a top club.'
Sanchez moved to Udinese in the summer of 2008 from River Plate and has scored five goals in 19 Serie A appearances for the Bianconeri this season.
The South American star is under contract with the Friuli outfit until June 2014.
Premier League big guns on alert as 'new Drogba' Lukaku targets switchPienaar to renew talks with Chelsea as Everton reject offer from TottenhamSampdoria want to take Chelsea youngster Van Aanholt on loanCHELSEA FC