William Saliba has stepped up his recovery from a serious back injury, with Arsenal hoping that he could return around the November international break.
The Frenchman has not played yet this season, having returned from the World Cup in the summer with a serious back issue.
Arsenal sent Saliba to be assessed by specialists in London and it was determined that surgery would not be required.
Recovery steps up
However, an "extended period" of rest was recommended and that has kept Saliba out of action for the first couple of months of the season.
The 25-year-old is still some way from being available, but it was positive news for Arsenal to have Saliba on the training pitch on Monday afternoon.
The centre-back was going through individual drills on the grass with two Arsenal coaches, away from the main group.
That is the latest step for Saliba as he builds cautiously towards a return to first-team action.
Arteta on Saliba's progress
"Now it's over a week [on the grass], I think, and he'll be managing that load," Arteta said on Monday.
"How many repetitions and sessions in a row he can do, but he's building now his capacity to good standards.
"Let's see in the next few weeks [if] we can start to introduce him with the team, and to see where we are to actually make him available."
Asked whether Saliba would be available after the international break next month, Arteta replied: "I don't know, we're still talking about weeks.
"That is very difficult to say if he can play just before or after that. It is a very specific healing process and I cannot tell you exactly how he is going to react to it."
Defensive options
In Saliba's absence, Ezri Konsa has made an impressive start to his Arsenal career alongside Gabriel.
The Gunners have also been strengthened in defence over the international break, with Ben White and Cristhian Mosquera recovering from injuries.
However, Piero Hincapie and Martin Zubimendi have provided fresh headaches for Arteta.
The pair picked up issues in Arsenal's warm-down after the win over Leeds and are unavailable for the Lille match.
Both players are undergoing scans on Monday to determine the severity of their issues.
