It emerged yesterday that Sports Direct sold 56.8 million shares, equivalent to 4.63% of the Debenhams share capital, on Tuesday.
That was the same day that transaction was made public and means Mr Ashley's company is likely to have made a gain in the region of £5 million on its investment, which was estimated to have been somewhere between £43m and £46m.
But Sports Direct has now also confirmed it has entered into a put option over more than 81 million Debenhams shares, or around 6.6% of the business.
Exact details over the duration of the option were not made public but Sports Direct said the maximum exposure it has to the deal is £64m.
If Debenhams shares are less than the agreed exercise price when the option expires Sports Direct can choose whether to buy the stock or pay a cash settlement. If the Debenhams shares are above the exercise price then Sports Direct will receive the premium and have no further obligations.
The sports and fashion retailer, founded by Mr Ashley after he left school, reiterated it wants to be a supportive stakeholder in Debenhams.
Reports have suggested Mr Ashley, owner of Newcastle United and a Rangers shareholder, is keen to introduce celebrity branded sportswear lines into the department stores
Brand ambassadors at Sports Direct include Olympic rower James Cracknell, former tennis players John McEnroe and Pat Cash and boxer Carl Froch.
Shares in Debenhams fell 1.3p, or 1.6% to 81.9p, with Sports Direct down 16p, or 2.2%, to 721p.
Separately, Primark, owned by Associated British Foods, said it had an "excellent" Christmas with sales up 14%.