Joe Allen played in Wales' 2-2 draw with Austria and scored in the match. He sat out the following match against Georgia, but has returned to Stoke with a hamstring injury.
Stoke City manager Mark Hughes believes that Allen "did too much" with Wales and that his fitness was "compromised".
"We're still checking on Joe, he hasn't trained with the group yet," he told Stoke's club website.
"We've just got to be a little bit careful with him; unfortunately he probably did a little bit too much with the Welsh squad.
"We would have given him an extra day's rest but he trained with [them] and that's probably compromised him a little bit so they have to be a little bit careful in that regard".
Meanwhile, Everton's James McCarthy played 90 minutes for Ireland against Georgia and then 81 minutes against Moldova.
However, the Irishman was just returning from groin surgery and Ronald Koeman believes that the player has been "massively overloaded".
"When James came back from Ireland the message from Everton’s medical staff was that he was massively overloaded. Now we have to handle a player who is massively overloaded," he said.
He then added: "Play him for 45 minutes, 60 minutes, but not 95 minutes after five to six weeks out, the second time 80 minutes! You are killing the player".