When teams struggle to score goals, you rightly have to worry. Palace have relied on Zaha for a large number of goals in the past few seasons, but he has been out injured a lot this year, and his contract is up in the summer. Unless Palace get a decent striker in the summer (assuming they stay up), they will likely struggle again next season.
I know they have been bad, but I thought they might have given Viera a bit longer (e.g. play against some of the weaker teams), but the directors have obviously lost faith in him.
I wonder whether Jesse March will be interested in a short term job.