The Portugal international is on a season-long loan from Porto, but has made just one substitute appearance for West Brom due to a groin problem.
Varela, 29, underwent surgery on the injury recently and is likely to be in contention for a return after next month's international break.
Head coach Irvine, who has seen his side take 10 points from nine Premier League games, is eager for Varela to get his first taste of top-flight action.
"Today was his first full session since coming back from injury so I'm really pleased about that," he told a media conference 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, who are without a win in four games in all competitions, travel to Leicester City for a Premier League fixture on Saturday.
