Boss Lee Clark told the club website: "I would like to have given Sean some game time.
"But how could I when the two lads in possession of the shirts have been playing the way they have?"
He added: "I'm gutted to lose Sean, because he's a very good footballer and has shown a terrific attitude all the time he's been here.
"It's a blow that he's gone back, but I respect their decision."
Huddersfield, meanwhile, have recalled 18-year-old winger Aidan Chippendale from his loan at Blue Square Premier side York City.
"Just like Reading with Sean," Clark said, "we wanted Aidan to play matches, but it didn't happen.
"We decided while we can't play him until the end of the regular season, it is of overall benefit for him to be brought back."
Source: BBC Sport
Source: BBC Sport