The prospect of a further penalty, especially more points being chalked off, is a serious potential blow as the Blues try to haul themselves away from the relegation zone where they found themselves following the first deduction announced in November.
Doucoure has been probably the most improved and arguably most important player in Dyche's Toffees team, since the former Burnley man took over from Frank Lampard almost exactly a year ago.
The ex-Watford midfielder had it seemed been consigned to the wilderness under Lampard and his days at Goodison Park looked to be numbered.
When Dyche took over he immediately restored Doucoure to his starting line-up and he has since become integral to the formation and tactics the Everton boss has favoured.
After that Doucoure scored some crucial goals in the Toffees battle to avoid relegation, including of course the winner against Bournemouth on the final day which guaranteed safety.
This season he is the team's leading scorer despite having missed six of the last seven matches with a hamstring problem.
His roving role as an advanced attacking midfielder or number ten type is proving to be a very useful one in Dyche's preferred 4-5-1 system.
Everton have only been victorious in one of those games he has missed, last night's 1-0 win over Crystal Palace in the FA Cup reply at Goodison.
Andre Gomes' free kick brought the Blues their first win since defeating Burnley on the 16th December last year.
But, despite that win the club still face a huge uphill task both on and off the pitch, particularly after Monday's news.
And losing a key player like Doucoure with another hamstring problem is a real blow for Dyche as he tries to plot a way out of the danger zone, preferably as soon as possible, given the potential prospect of a further points deduction down the line.
With the side struggling badly to score goals and the team's main centre-forward Dominic Calvert-Lewin enduring a serious drought that has seen him fail to net since scoring at West Ham in October, losing Docuoure is an even more serious problem.