Alun Wyn Jones and George North are in line to return for Ospreys' crucial Pro14 match against Cardiff Blues.
Neither has played since Wales' Grand Slam-clinching Six Nations win against Ireland on 16 March.
Both face fitness tests, but lock Jones is set to return after his knee problem while wing North is close after breaking a bone in his hand.
"They have had some contact this week, we will check again on Thursday and Friday," said coach Allen Clarke.
"We need to take that to another level before we finalise selection.
"It would be great if they could come through but we are not in a position to confirm that yet."
Jones and North were both injured in the same passage of play early in the 25-7 defeat of Ireland in Cardiff.
North left the field while Jones played on with a bandaged knee to lead Wales to a fourth Grand Slam in 14 years.
Saturday's clash with the Blues in the Cardiff Judgement Day double-header will decide who finishes fourth in Conference A and wins a play-off place to qualify for the 2019-20 European Champions Cup.
Ospreys are one place ahead of the Blues after a run of three wins, and North is keen to play after his lay-off.
"It's been a long few weeks and it was not a straightforward break," he said.
"I have put in a good block of training and I will be up for selection and hopefully I will get my name on the team sheet somehow."
Coach Clarke added: "If you look where we were prior to the Six Nations with the turmoil and off-field distraction we dropped down the ladder of the league table.
"When the boys came back in we have really built some momentum again with three bonus-point victories and had a wonderful tour of South Africa.
"We are just happy to have a game that has significant meaning. This region has a great history and this is a chance to put us back on the map."
Cardiff Blues hope to have Wales hooker Kristian Dacey and influential Kiwi number eight Nick Williams fit again.
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