Labrune was among four people arrested on Thursday as part of an investigation into Andre-Pierre Gignac's transfer to the club in 2010, with judicial officials said to be attempting to establish whether members of Marseille's hierarchy received illicit commissions at the time of the striker's switch from Toulouse.
Marcelo Bielsa's men could be forgiven for being distracted by the off-field issues enveloping the club, however, Marseille and Gignac – who has 10 Ligue 1 goals this season – cannot afford a slip up versus a Bordeaux side that sits just four points behind them in fourth position.
The Provencal outfit could have dropped off the top by the time they take to the pitch at the Stade Velodrome on Sunday, with second-placed defending champions Paris Saint-Germain and Lyon in third both having the chance to leapfrog Marseille with their games taking place earlier in the weekend.
PSG kick-off the French top flight's return from the international break with a trip to the Stade Saint-Symphorien on Friday to take on a Metz team that has surprised many with their strong form upon promotion to Ligue 1 following a six-year absence.
Laurent Blanc's visitors have won their last six in all competitions, recovering well from a below-par start to the season and are now just one point behind Marseille on the back of their 2-0 win in 'Le Classique' 10 days ago.
And goalkeeper Salvatore Sirigu believes the capital club are turning the corner.
"We've really paid for the errors we've committed [earlier in the season]," Sirigu told Ligue 1's official website. "But it has also helped us to wake up and realise where we need to improve and where we need to work the most. We are progressing."
Lyon will be expected to extend their unbeaten run to 10 games with a victory at Bastia, while Nantes host Saint-Etienne in a meeting between two clubs that have 18 Ligue 1 titles between them and are both looking to keep pace with the top three.
At the other end of the table, struggling Guingamp host Breton rivals Rennes hoping for a repeat of the performance that saw Jocelyn Gourvennec's men claim a 2-0 win over their neighbours in the Coupe de France final in May.
Lorient welcome Lens to the Stade du Moustoir in a battle of the league's two bottom clubs and Caen visit Monaco as the Normandy club aim to pull away from the relegation zone.
Elsewhere, Nice meet Reims and Toulouse visit Montpellier.