The Foxes withdrew their interest in the 22-year-old last week but, with Celtic one of a number of teams interested in the player, Watkins has told the club's website he still not 100% sure where Cox will be plying his trade come August.
"There was nothing to suggest he wouldn't have been (at pre-season training) and he, like all the other squad players who are under contract, will report for training on Monday," said Watkins.
"With regards to Simon's future, though, it is still in the lap of the Gods.
"The last thing I am aware of was when Leicester withdrew their interest.
"There are several other clubs interested but managers have also moved and those who were expressing an interest in him have to get settled in their new club before they contemplate getting involved in the transfer market."