The German defender was forced off with an ankle injury during last weekend's 2-1 FA Cup semi-final win over Reading.
And Wenger had rated the 30-year-old's chances of playing against Jose Mourinho's men as only 50/50 and Gabriel was set to take his place.
, & , training session this morning. More pics
— Stuart MacFarlane (@Stuart_PhotoAFC)
But the defender was seen training alongside Alexis Sanchez and Mesut Ozil this morning and looks set to captain the side.
Chelsea will arrive at the Emirates with a 10-point lead at the top of the Premier League table and need just two more wins to claim the title.