Iraola, Alonso, Silva and Glasner are all out of work, or scheduled to be without a club, by the end of the season which means Chelsea will not be required to pay compensation.
Glasner is leaving Crystal Palace when his contract expires this summer and is understood to be open to staying in England.
Similarly, Iraola has confirmed he will depart Bournemouth at the end of the season.
The Spaniard is Crystal Palace’s first-choice candidate to replace Glasner and the Eagles have already held extensive talks with Iraola.
However, Iraola is taking time to weigh up his future amid interest from Palace and Chelsea – while sources have also indicated the 43-year-old is open to going into next season without a club which would leave him available to take any mid-season vacancies.
Silva’s Fulham contract expires this summer but he has been offered a three-year deal by to stay.
The Portuguese is reported to have options abroad, while clubs in Saudi Arabia are also understood to be keen on Silva if he leaves Craven Cottage.
