Cue an outbreak of worry about what could happen at the autumn test of the covenants.
Wales Six Nationssuccessstoryory is in stark contrast to their autumn Test series results.
That means the 24-year-old will miss the summer and autumn Test series, which involve three games against Australia.
Healy has been itching for a start after recovering from a nasty hamstring tear in September that ruled him out of the autumn Test series.
Dan Biggar has been recalled to the Wales squad for the autumn Test series.
Defeat against Tonga on Saturday would leave Scotland without a win in this autumn Test series.
Rugby Park will host Scotland's autumn Test meeting with Tonga on 22 November.
Sam Warburton says he does not know if he will be Wales captain for the autumn Test series.
Head coach Andy Robinson is remaining tight-lipped on who will captain Scotland for the autumn Test series.
Low, 27, does not require surgery but will not be fit for consideration for Scotland's autumn Test series.
Wales suffered shock defeats to Argentina and Samoa in the first two games of their autumn Test series.
