Atlético Madrid midfielder Saúl Ñíguez will fill in at left-back this weekend, as Filipe Luís is a serious doubt for their trip to Girona following his recent injury during the club's Champions League group stage match against AS Monaco.
The 33-year-old was able to complete the full 90 minutes as goals from Koke and Antoine Griezmann inflicted another defeat onto Thierry Henry's side, confirming Atléti's place in the knockout stages of the competition.
However, the club confirmed on Friday that Luís would be a serious doubt for their return to La Liga on Sunday as he suffered a muscle injury in the aftermath of the game.
Regular first team full-back Lucas Hernández has recently returned from injury. However, Diego Godín and José Giménez are still out, so the Frenchman will once again fill in at centre-back.
Santiago Arias remains the club's only available right-back too, so Simeone will not be able to ask either the Colombian or the injured Juanfran to swap wings for the time being.
That leaves Atlético desperately looking for any left-footed player who can temporarily fill in, but they only have three currently available, and it's hardly worth even entertaining the idea of Griezmann joining the defence.
That leaves it as a toss of a coin between Saúl and summer signing Thomas Lemar.
As Simeone knows that he can bring Koke or Rodri in to partner Thomas in midfield - only Vitolo is available to replace Lemar - the Argentine head coach appears to have settled on moving Saúl to defence as a short-term plan.