Boro head into Saturday's npower Championship trip to Leeds sitting just a point off the automatic promotion places, and will approach the winter window having been linked with a loan move for former star Stewart Downing with the likes of Rhys Williams, Muzzy Carayol, Julio Arca and Curtis Main all close to returning from injury.
But Mowbray told the Northern Echo: "We're not really in the market place to add more players in January.
"We're going to have some real selection headaches about who's getting left out and who's sitting in the stands as opposed to on the bench, so I'm not here looking at trying to get a load more players in January.
"We're trying to manage the squad - although if there are any outs, there might be an in.
"If not, then the likes of Luke Williams and Adam Reach, who have been on the periphery for the last month or two, will probably get an opportunity."