Boro's scouting system has undergone a major overhaul in recent months and the manager is now receiving regular scouting reports from teams throughout the country and leagues around the world.
And while he's not anticipating any dramatic activity with the window now at its halfway point, he says it's vital to be poised to make a move if the need arises.
"We're always looking," Mowbray said. "We have lists of players that potentially we'd like to sign.
"I talk to Steve (Gibson) on the phone a lot and if there's a player at the right price who we think can make a difference, he's never said there's no money available.
"And yet we don't want to sign players for the sake of it. It would only be someone who's a stick-on in the team, who and can come in and play and who the guys who get left out will understand that this player is making a difference.
"Otherwise it's very difficult saying to the players who've done well for us that they're getting pushed aside just because we can."
Mowbray insists the time for squad building is in the summer before the campaign gets underway and he's not a fan of making wholesale changes in January.
However, he is a firm believer that all his players have their price and if an offer comes in that would enable him to improve in other areas, it will be considered.
He said: "If the phone rings for any of our players and we've got decisions to make on whether we want to sell anybody or keep them, we'll take stock.
"Obviously we don't want to rock the boat too much when the team is doing reasonably well, so I'm not sitting here anticipating any of our major players leaving.
"There'll be no enforced sales anyway - I've spoken to the chairman and he's quite comfortable at the moment where we are.
"The chairman is very, very supportive and sees we're in a healthy position. If someone does leave it will be because we feel it will allow us to strengthen elsewhere.
"Because where we are in the league right now we have a responsibility to push on and try and see how far we can take the season, not to be selling our best players.
"Yet at the same time, if we feel it's right and we can improve the team, then we'll look at that."