The two players both missed Sunday's Premier League game.
Grealish, 20, has missed Villa’s past five games since twisting his ankle in training last month, just a few weeks after sitting out three matches while recovering from a bout of tonsillitis.
The promising playmaker has only made three appearances for the club this calendar year as a result, but while Garde is waiting for the doctors to give a fresh update on his status, he is hoping to have his star prospect back in training during the international break and fit to face Chelsea on 2 April at Villa Park.
Asked about Grealish’s recovery timetable following Sunday’s 2-0 home defeat to Tottenham Hotspur, the Frenchman told avfc.co.uk: “Unfortunately for the team and for me, there is no more news on Jack.
“The doctor told me he had a problem with his ankle and he needed to treat that. I am waiting for his return.
“It could be another ten days or two weeks maximum hopefully.”
Grealish was far from the only Villa player missing through injury on Sunday afternoon, as Carlos Sanchez [hamstring], Libor Kozak [ankle], Adama Traore [foot] and long-term absentee Jordan Amavi [knee] all remain sidelined.
Gabby Agbonlahor was also surprisingly missing from the matchday squad after starting the previous six matches, with Garde confirming that the long-serving striker picked up a knock on his thigh during training late in the week.
Rudy Gestede subsequently made his first Premier League start since early January, and while he struggled to offer the same kind of impact as he has made off the bench over recent weeks, the Villa boss seemed satisfied enough with his performance.
“Gabby trained on Thursday, but he came on Friday morning with an injury - a thigh problem,” Garde told avfc.co.uk. “He was not fit for selection. The options were today not too many, but Rudy had a good game.
“He has some different skills that we tried to use. It was not too bad.”