Saints boss Chris Boyd admits he isn’t sure what his best side is as he currently has so many options at his disposal.
But he is desperate to find the perfect formula for Saturday afternoon’s crucial French test at the Matmut Stadium.
Saints square up to Lyon, knowing they are likely to need a win the qualify for the Champions Cup quarter-finals.
Ulster, Saracens, Gloucester, Glasgow, Munster and La Rochelle all join Saints in the race for the three best runners-up spots.
And that means it is likely to be a see-saw weekend in Europe.
But Saints are well aware the only thing they can influence is their outcome at Lyon, who are now out of the competition following their Pool 1 defeat at Leinster last weekend.
And Boyd said: “We can’t control what will happen elsewhere but at the end of the day we’ve got to do one better than Gloucester do at Toulouse.
“It might be that a bonus point will get us there, it might be that four points does it or even five points might not get us there.
"What we can control is our outcome and performance and we’ll go there with the best team for what we think is the right way to play against Lyon at home.”
Saints are set to welcome back the likes of Dan Biggar, Alex Waller and Tom Wood, who were all rested for the 33-20 home win against Benetton last weekend.
“Rest and rotation goes on all the time anyway, and I don’t even know what our strongest team is to be honest because we’ve got three loosehead props all playing well, three tighthead props all playing well,” Boyd said.
“Mikey Haywood will probably come back in the hooker position and who knows what will happen in the back row and second row?
“We’ve got some choices and we’ll pick the team that we think is important to play Lyon there. We certainly won’t be resting people for the sake of resting them.”