The Dutch giants are believed to have made an enquiry about the utility player last season, having left them back in 2014 to join the Red Devils.
It's understood United boss Jose Mourinho rejected any possibility of a loan deal at that time, with his squad seriously depleted by injuries and Blind's ability to fill a wide variety of roles invaluable.
Blind has been on the periphery of the starting eleven so far this campaign but produced a competent wing-back display in Wednesday night's comfortable Champions League win over CSKA Moscow.
The Netherlands international has less than 12 months remaining on his present deal and is fully expecting United to take up their option of a further year, although serious talks have yet to take place.
Ajax's bosses enjoy good relations with their counterparts in Manchester, who are wanting to be kept in the loop on Blind's situation, should Mourinho ultimately decide the 27-year-old Dutchman can move on next summer.