Rob Page's side have picked up just one point from their five matches in Group A4, drawing 1-1 with Belgium in June.
Defeat for Wales would see them return to Group B after just one campaign at the top level.
Poland head into Sunday's clash three points ahead of Wales, although they do have a significantly worse goal difference.
A 2-0 home defeat at the hands of the Netherlands on Thursday night means Poland's future is still uncertain, needing a point to survive relegation.
Page has said that Wales' key man has trained "really well" and has "put himself into a position where he could potentially start."
Ben Cabango could be recalled to fill in at centre half with Joe Morrell playing in midfield.
Czeslaw Michniewicz is expected to make little to no changes to his side that lost at home on Thursday night.
Szymon Zurkowski is available for selection again after missing Poland's previous game through suspension.
Hennessey; Cabango, Rodon, Norrington-Davies; Roberts, Morrell, Smith, Williams; Bale, Moore, Johnson (3-4-3)
Szczesny; Bednarek, Glik, Kiwior; Frankowski, Krychowiak, Linetty, Zalewski; Szymanski, Zielinski; Lewandowski (3-4-2-1)
Naming Bale as key player is a bold shout considering his recent injury concerns, but he cannot be counted out.
Bale is Mr Reliable for Wales, always putting in big performances when it matters most.
The Qatar World Cup will be Wales' first since 1958, ending a long wait for the nation.
Their opening group game against the United States is just 58 days away. Risking Bale's fitness in the hope of Nations League survival would be a huge call for Page to make, but one that could reap enormous benefits for his side.
With 40 goals in 107 games in a Wales shirt, Bale sits comfortably as his country's all time leading goal scorer.
Lewandowski has been one of Europe's elite strikers for the past decade. 312 Bundesliga goals in 12 years puts the Polish striker second in the league's history, only behind Gerd Muller.
His electric start to life in Barcelona has come as no surprise, scoring 11 in eight games for La Blaugrana.
Despite his stellar club form, Lewandowski has scored just one goal in this year's Nations League campaign, scoring the opener in a 6-1 defeat against Belgium.
Lewandowski's presence in attack will still strike fear into Welsh hearts.
With Poland needing one point to confirm safety, a goal from Lewandowski will go a long way to helping his country.
Where is the game being played?
The game will take place at the Cardiff City Stadium,, Cardiff.
What time is kick-off?
Kick-off is at 7:45pm GMT, Sunday 25th September.
How can I watch?
UK viewers can watch the game live on S4C and Premier Sports.