Van Gaal revealed that Carrick needed time off following two games in the space of three days against FC Midtjylland and Arsenal last week.
Carrick, usually a midfielder, had been playing at centre-back in recent days following a slew of injuries at Man United. Timothy Fosu-Mensah covered at the back in Carrick’s absence on Wednesday but van Gaal insisted that the 34-year-old wasn’t injured:
Louis van Gaal on Michael Carrick: "He is rested because he played two matches in a row. He's not the youngest so we take no risks." #mufc
— Manchester United (@ManUtd) March 2, 2016
Fosu-Mensah impressed in central defence against Watford as he got in the face of The Hornets’ Odion Ighalo.
It was the more experienced Daley Blind, in fact, who struggled up against the strength of Ighalo and Troy Deeney.
United certainly rode their luck at times at Old Trafford and they were unlucky not to concede several goals. You get the sense that van Gaal will be keen for Chris Smalling to return from injury as soon as possible.