With the defender also being monitored by Brentford and Bologna, who began investigating the possibility of recruiting him over the weekend, officials at the Edinburgh club are confident of receiving a premium sum for the 20-year-old should he move on.
Although United have not submitted a bid - or officially opened talks with their counterparts north of the border - members of Paul Heckingbottom’s backroom staff are known to have been keeping tabs on Doig for some time.
However, should they decide to show their hand, they will face stiff competition from teams both at home and abroad which is likely to drive up his asking price. Nottingham Forest, who beat United on penalties in the Championship play-off semi-finals, are also thought to have maintained a watching brief on Doig over the past few months as they plot their return to top-flight football.
Heckingbottom has identified “six or seven” vacancies within his squad which need addressing before the new season gets underway. Some of those are likely to be filled by graduates of Bramall Lane’s development programme, with the likes of Will Osula and Kyron Gordon both making significant progress last term.
But if Heckingbottom gets his way, the majority of the positions he has identified are set to be taken by external candidates - pointing to a potentially busy summer in the transfer market.
Capped eight times by Scotland at under-21 level, Doig has made 78 senior appearances for Hibernian since breaking into their first team.