Celtic progressed to the Premier Sports Cup quarter-finals with a 4-0 win over Dundee United at Tannadice on Saturday evening.
Goals from Auston Trusty, Camilo Duran, Sebastian Tounekti, and Benjamin Nygren ensured their safe passage to the last eight.
But there were some notable absentees from Martin O'Neill's matchday squad, with both Yang Hyun-jun and Anthony Ralston not included.
Asked about the duo post-match at Tannadice, O'Neill explained: "Tony was with us, but you can only pick so many.
"Yang was really stiff, very, very stiff after training on Thursday and missed yesterday's [Friday] training.
"But we're hoping that he should be OK for Wednesday."
Celtic face LASK in the first leg of their crucial Champions League playoff this coming week.
"They're a very fine side, they're very, very strong," O'Neill continued. "Ideally, it would be great if some of the lads who have come in now had a bit more practice with the team, in that sense. But it is what it is.
"We have to be ready regardless."
Read more:
Saturday night saw O'Neill give debuts to new Celtic signings Mika Baur and Haissem Hassan.
"One can never plan these things, but the idea was at some stage or another that Hassan would maybe get the last 20 minutes," he added. "He's done very little training since the World Cup.
"At least Mika has trained and played pre-season, so he's more up to speed with things, got a little bit longer.
"And of course, there's always the concern that somebody just stepping in, straight in, has an injury of some description, a muscle injury or something like that, and that's what we had to be careful of. But overall, yeah, at least they got on the field of play."
