Wales have injury concerns over captain Matthew Rees, James Hook, Ryan Jones and Morgan Stoddart before Saturday’s Six Nations match with Ireland.
All four have been taking a “limited part” training, but Wales are hopeful they will be fit to start in Cardiff.
Back-up hooker Richard Hibbard picked up a should injury playing for the Ospreys on Saturday, so regional team-mate Huw Bennett has been called up.
Jonathan Thomas suffered a dead leg in that game and is being monitored.
Prop Adam Jones has not been called up despite returning on Saturday for the Ospreys after a seven-week absence with a shoulder injury.
Hooker Rees has been hampered with a hamstring problem since Wales’ 16-24 over Italy in Rome on 26 February, while versatile three-quarter Hook (calf), number eight Jones (calf) and wing Stoddart (shoulder) have also been nursing knocks which have hindered their training schedule.
“Both Matthew [Rees] and Morgan [Stoddart] have responded well to extensive treatment since picking up their injuries against Italy,” said Wales national performance medical manager Prav Mathema.
“Matthew has a slight hamstring problem and Morgan sustained an injury to his shoulder during that match, but the medical staff has managed both players very well and together with the hard work they have put in so far we expect both to be available for Ireland.
“Richard [Hibbard] has a shoulder problem sustained during his outing for the Ospreys this weekend and he needs rest at the moment although he too should be okay for Saturday.
“Jonathan [Thomas] also picked up his injury at the weekend and we will further assess him towards the end of this week.
“The issues with Ryan [Jones] and James [Hook] just mean they have taken a limited part in some sessions so far during our preparation but, again, both will be fine.”
Centre Jonathan Davies, who missed the Italy victory with a hamstring injury, has been able to take a full part in training after returning to the squad.
His presence poses one of the few selection options to coach Warren Gatland as Wales seek a third consecutive win in this year’s championship.
Adam Jones on the attack for Wales
Adam Jones returned to action for the Ospreys against Glasgow
In Davies’ absence, Hook switched from fly-half to outside centre and Stephen Jones came back at fly-half, having been dropped to the bench following Wales’ opening 26-19 defeat by England when they won 24-6 against Scotland.
Gatland must now ponder his fly-half and centre options amid an ongoing debate over Jones and Hook’s rival claims to the pivot role.
The coach had also been urged to recall prop Jones after the experienced loose-head proved his fitness with 22-minute outing as a replacement in the Ospreys’ 37-6 win over Glasgow on Saturday.
Former Wales and Lions scrum-half, Robert Jones, said Jones should at least be on the bench against Ireland at the Millennium Stadium on Saturday.
“We’ve got a lot of props in terms of the overall set-up, but only one or two world-class props,” Jones said on BBC Wales’ Scrum V programme.
“And I think if he’s available, whether as a bench role or not, I think he should be brought in.”
Scarlets wing George North and Newport Gwent Dragons back-row Toby Faletau also returned at the weekend but have not been added to the Wales squad.
North, 19, revealed on Twitter on Sunday that he had driven home to Anglesey while Wales’ players prepared to return to their training base at 1800 GMT that day so it is unlikely he will earn an instant recall.
North underwent shoulder surgery following Wales’ November Tests in which he made headlines and came back in their 26-15 defeat at Leinster on Friday, 4 March.
Uncapped Faletau was named in Wales’ initial Six Nations squad only to damage an ankle against Glasgow in the Heineken Cup in January.
Wales squad:
Forwards: Paul James (Ospreys), John Yapp (Blues), Craig Mitchell (Ospreys), Ryan Bevington (Ospreys), Scott Andrews (Blues), Matthew Rees (Scarlets, capt), Richard Hibbard (Ospreys), Huw Bennett (Ospreys), Alun Wyn Jones (Ospreys), Bradley Davies (Blues), Ryan Jones (Ospreys), Sam Warburton (Blues), Jonathan Thomas (Ospreys), Andy Powell (Wasps), Josh Turnbull (Scarlets), Rob McCusker (Scarlets), Dan Lydiate (Dragons).
Backs: Mike Phillips (Ospreys), Dwayne Peel (Sale), Tavis Knoyle (Scarlets), Stephen Jones (Scarlets), Rhys Priestland (Scarlets), James Hook (Ospreys), Jamie Roberts (Blues), Jonathan Davies (Scarlets), Shane Williams (Ospreys), Morgan Stoddart (Scarlets), Lee Byrne (Ospreys), Leigh Halfpenny (Blues).
