Lisbon is the favourite to host an eight-team Champions League knockout tournament in August, if it is given the go-ahead by governing body Uefa, reports BBC Sport.
Uefa is planning to move the final from Istanbul, where it was due to be held on 30 May, for the new format.
The Europa League final, due to be held in Gdansk, Poland on 27 May, is likely to be moved to Germany.
Uefa's executive committee will make its decision on 17 June.
The Champions League final would be played on 23 August, with the Europa League final taking place on 21 August.