Surface fears prompt Exeter to omit Jack Nowell from Saracens showdown

• Club wary of Allianz Park’s artificial pitch given player’s chronic knee issue• England wing in Dubai as team-mates prepare for top-of-the-table clashExeter’s grand slam-winning wing Jack Nowell will miss Saturday’s top-of-the-table Premiership fixture at Saracens because his club still feel it is too risky to play him on artificial pitches. The England three-quarter has had a long-standing knee issue and is enjoying a break in Dubai rather than preparing for the game at Allianz Park.Nowell also sits out away matches at Newcastle for the same reason, although the Exeter head coach, Rob Baxte…