However the move surprised many, coming as it did just a couple of days after the club had won their Round 3 contest 20-13 at Bordeaux-Begles.
Now the trick is for Murray - who remains at the heart of their pack as a player - to show he also has the tactical awareness to try and plot the European double and go on and get them out of domestic trouble.
The win at Stade André Moga brought an end Mont de Marsan's 11-match tournament losing run - the worst by any French club in the competition - while also gaining a measure of revenge for Bordeaux-Begles' 17-12 win in the Top 14 last month with Raphael Ibanez's club now rooted to the foot of the table.
• Victory over Bordeaux ended an 11-match losing streak in this tournament for Mont-de-Marsan.
• Bordeaux have suffered five defeats on the trot on this tournament, scoring an average of just 12 points per game in these losses.
• Against fellow French sides, Bordeaux have lost their last four games in this competition, their last victory coming against Dax in 1999.
• Mont-de-Marsan have made a competition low 54 tackles per game so far this season.