Varela, who moved to the Baggies on a season-long loan from Porto in the summer, has only managed to make one appearance for the club so far, but Irvine is hopeful that the Portuguese winger could be available for selection by the end of November.
"Today was his first full session since coming back from injury so I'm really pleased about that," the West Brom boss told reporters on Thursday. "He's obviously a long way away from being ready to play in the Premier League. He will need time. He is one who, during the international break, we will try to top up.
"I wouldn't have thought there is any chance [of him playing] before then.
"Porto have been happy for him to stay here - they've been involved with the decisions we've made - and he's a lovely lad, he's good to have around the place and, without knowing him too well, he is desperate to get out there and start playing."
West Brom take on Leicester City on Saturday.