According to Transfermarkt.co.uk, Gregory is out of contract at Millwall this summer.
The Mirror (print edition, page 49, April 2, 2018) claimed that Derby County are interested in signing the 29-year-old striker in the summer transfer window (click here to read more).
It was reported that Derby are planning to secure the services of the former FC Halifax Town striker for around £750,000.
The Daily Mail reported in March that Sunderland and Sheffield Wednesday want to sign Gregory this summer.
Sunderland, Wednesday and Derby will now have to pay a decent transfer fee, as Millwall have activated the option to extend Gregory’s contract, meaning that he will now remain at The Den until the end of next season, as announced on their official website.