"If he was a front row forward he would have stayed on," Wales forwards coach Robin McBryde quipped. He added Williams was to train on Tuesday. Meanwhile, Van der Flier was hurt on Sunday in the home win against France, and came off after only 24 minutes.
He was replaced in the squad on Tuesday by Dan Leavy, who hasn't played since January because of a calf injury but the Ireland coaches want to assess him. Jack Conan stepped in for Van der Flier and scored a try against France, while British and Irish Lions flanker Sean O'Brien, who started in the wins against Scotland and Italy, was also in the squad.
Fullback Rob Kearney, who was a late withdrawal after a calf tightened, was expected to train on Tuesday and be available to face Grand Slam-chasing Wales on Saturday in Cardiff. Backup flyhalf Joey Carbery was also apparently recovered from a hamstring injury and pushing to be available for selection.
Assistant coach Greg Feek said they can handle the shorter six-day turnaround. "The short turnaround is what it is, it doesn't affect our preparation," Feek said. "We've done it before and we'll see how (training) today goes. Make sure we get those crucial boxes ticked."
McBryde said Wales will have to be a lot more accurate against Ireland than it was against Scotland. Wales conceded 11 penalties to Scotland under pressure, five in its own 22, but Scotland preferred to go for a try than kick for points.
"Our discipline has to improve because we gave Scotland numerous opportunities," McBryde said. "If we do that with Ireland they will take them. We have got to be squeaky clean." The lineout was also shaky again, losing one throw-in to the Scots. Lock Cory Hill was preferred for the England win on his lineout ability then was injured, and Beard returned to face Scotland.
"(Lineout is) not our strongest suit at the moment," McBryde admitted. "We didn't quite get it right against Scotland. "Ireland are a very good set-piece side, and (Peter) O'Mahony is very good and astute in the air. You don't mind it when the opposition earn the steal, it's most disappointing when you lose it through the drill not going right.
"Adam Beard is our lineout caller. He really stepped up. He's grown massively. Coming into the campaign, he hadn't had a lot of gametime under his belt because of concussion. Cory Hill is mentoring him. This is where you get tested, against a team like Ireland."
The match will be McBryde's last in the Six Nations, as he's stepping down with coach Warren Gatland after the Rugby World Cup this year. He hopes to finish with a Grand Slam. "There's a respect for (Ireland) but an extra edge as well when you know who you are playing against. You always want to get one up on your neighbor," he said.
"There will be a number of personal battles on Saturday and some scores to be settled."
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