Administrators of the League One club revealed on Thursday that former Football League chairman Harris and a group of financiers had made an offer to take over at Fratton Park.
However, the League have now confirmed that they will only be considering a bid that has already been made for the club by the Pompey Supporters Trust.
"Given that the Football League's Insolvency Policy prohibits a club from beginning two consecutive seasons in administration, the board took the view that any change of preferred bidder at such a late stage would only create further uncertainty and was not in the wider interests of the League and its member clubs," read a statement.
"Therefore, the League has informed the Administrator that it will not currently consider transferring the club's share in the Football League to a new bidder. This means that in the event that the PST bid does not succeed and Portsmouth do not exit administration before the end of the current playing season, the club will lose its membership of the Football League."
Portsmouth entered administration nearly one year ago.