The club are working hard to identify talent in key areas of the field but Karanka says there wll be no panic buys.
He said: “The club and myself are watching players to strengthen the squad but we have one thing clear – players who come must be better than the players we have at the moment.
“We’re working on other players in other leagues and when the window opens in January we will try to get players.
“If some players arrive it will be good and if they don’t I’m happy with my team. We will see on January 31 if we have any more players.
“But if one player or two players come here, they will be better than the players we have here now.”
Karanka has already hinted that any incoming transfers are likely to be balanced by players leaving.
“I said to the club before I came here that I don’t like having too many players because a lot of players are trying 100% and it’s difficult for me to choose 18 for each game,” he said
With regular No 1 Jason Steele likely to be sidelined until January with his ankle injury, Karanka is keen to extend Shay Given’s loan from Aston Villa, which ends after the Bolton game on New Year’s Day.
Boro defender Jonathan Woodgate is hoping to prove his fitness following a thigh problem in time to take his place in Middlesbrough’s squad for today’s visit to Millwall.
Striker Marvin Emnes missed the Brighton defeat with a slight hamstring injury, but has a chance of returning.