Grealish was left out of the squad against Watford and Southampton for a breach of club discipline after he was photographed partying in Manchester just hours after Villa's 4-0 defeat at Everton last month.
It was not the first time the young midfielder had hit the headlines for his off-field behaviour
Grealish was pictured earlier this year on his back in the street during a holiday in Tenerife, for which he was reprimanded by Villa
The 20-year-old has also been pictured partying in Marbella and seen inhaling nitrous oxide, known as laughing gas or 'hippie crack', from a balloon in a photograph taken last year
Grealish played for the Villa under-21 team on Monday night and has now served the punishment for his latest misdemeanour, so he will be back in contention against Arsenal on Sunday
Garde said: "Like all other players training with the first team after the under-21 game, Jack is back and Jack is available for selection
He is in contention to start like 18 or 20 players
"He is a talented young player but only Jack knows if he has learned
"I'll still be close with him
I have the feeling Jack needs to be more disciplined, this way I feel he can improve his game."
Arsenal, one of Garde's former clubs, will arrive at Villa Park on a high after beating Olympiacos 3-0 in Athens to qualify for the Champions League knock-out stages ahead of the Greek side
Garde is aware of the size of the task facing his bottom-of-the-table Premier League team and he believes the Gunners are capable of going on to win the Barclays Premier League this season
"It is a long time ago since I was there
Probably everything has changed there - except one," said Garde, referring to his old manager Arsene Wenger
"I know very well the team and the players but we will need more than that to get points from them
"They are very comfortable away from home and have scored more away from home which shows how dangerous they are
"They can win the title of course
Now they are qualified for the Champions League (knock-out stage) they will have to concentrate on both targets which not easy
Maybe it is the year they can fight for the title until the end."
Source : PA
Source: PA