Marseille's last game ended in an embarrassing 3-2 loss to strugglers Lorient at the Stade Velodrome after the former European champions, who are second in the standings, threw away a two-goal lead in the final 15 minutes.
Media reports had suggested a dejected Gerets left the club for 36 hours to get over it.
"It's a nonsensical piece of news and it's totally unfair," Gerets told the club's website.
"It's false. If I had to leave, it's just for personal reasons, I had a plane to catch. Everyone at the club, officials and players, were aware of that."
"I've calmed down but I'm quite frustrated by what was reported. I do not need to run away. I've been looking everyone straight in the eyes for 30 years," the former PSV Eindhoven player and coach added.
FULL TRUST
Gerets, 54, joined Marseille in September 2007, leading the club from 19th to third in the Ligue 1 standings at the end of last season, which earned him full trust from chairman Pape Diouf.
"My feeling is that the team have always been able to bounce back. I know Eric Gerets, I know he will not let the situation drag on and will get things back under control," Diouf told Marseille's website.
Gerets may have to make do without injured Ivory Coast striker Bakary Kone, who is a doubt to face seventh-placed Lille. Kone has scored six times in the league this season.
"I'm doing my best and I hope I will be ready for this match against a very solid team," said Kone.
Marseille are seven points behind leaders and seven times champions Olympique Lyon, who visit Paris St Germain on Saturday.
Lyon will be without Argentine forward Cesar Delgado, who is sidelined for two weeks with a groin injury, while eighth-placed PSG will be hoping in-form striker Guillaume Hoarau and winger Ludovic Giuly will be able to breach the visitors' defence.
Also on Saturday, sixth-placed Girondins Bordeaux, beaten 2-1 at Lyon last weekend, take on Stade Rennes, who are third and have not lost in 12 league matches.
