Scholes, who was linked with a comeback for much of the season after hanging up his boots in the summer, returned to action last week in the FA Cup and is expected to make his Premier League return against Bolton this afternoon.
Hovever, Reo-Coker insists that he did not expect the former England international to change his mind.
"Scholes is a tremendous player," he said. "He always has been, although it was a big surprise to see him change his mind about retiring.
"But it's Manchester United, which is such a tight-knit family club in the way the generations have come through.
"You get the feeling Scholes, Nicky Butt, the Neville brothers and David Beckham would do anything to help the club. So from that point of view, maybe it shouldn't have been such a surprise."
Bolton are currently a point from safety in 18th place in the Premier League.