The Toffees boss will look to recruit a couple of new faces before the window closes as he tries to bring European football back to Goodison Park next season, but the urge to acquire a marquee name to aid that quest is one Martinez is keen to avoid.
He was impressed with how his players negotiated the busy Christmas and New Year period and Saturday's 4-0 FA Cup win over QPR provided an indication of the strength in depth at the Spaniard's disposal.
So while other managers chase additions to inspire a squad down the season's final stretch, Everton's manager is more mindful of upsetting the apple cart.
"Bearing in mind that we had five games in the space of 14 days, the squad has reacted in a great manner," he said.
"The last thing we need is to bring someone in that can dislodge that mentality and that feeling in the dressing room.
"This window we've got something to lose rather than something to gain with adding players for the sake of it, so it's going to be very well-measured and obviously we don't want to lose any of the top performers this season."
Instead, Martinez's top priority will be ensuring the likes of England duo Leighton Baines and Ross Barkley are still at the club come February.
And with Everton currently fifth in the Barclays Premier League table ahead of this weekend's clash with Norwich and on course to qualify for a continental competition of some description, Martinez retains belief his prized assets will be staying around.
He said: "We had a very good start to the season. The youngsters have developed extremely well to have important roles in the side and the senior players have performed really well.
"In January what we want to do is make sure is that we don't lose any of the top performers that we had in the first part of the season.
"If anything, we want to bring maybe one or two new faces where they could cover an area where we're going to be a little bit weaker in the second half of this season."
One player who Everton have been strongly linked with is Spartak Moscow's Aiden McGeady.
The Republic of Ireland international, 27, is a free agent in the summer and reports suggested Martinez is on the verge of agreeing a pre-contract to bring the ex-Celtic winger back to these shores.
The Toffees boss denied a medical was imminent this weekend, though, and added: "I'll never, ever be disrespectful and speak about a player who is registered with another club. Aiden is in that category."
However, McGeady would certainly not fit the bill for the type of player Martinez is chasing in the coming month.
A central midfielder and another forward to compensate for the long-term injuries to Darron Gibson and Arouna Kone are high on Everton's wishlist, but maintaining a harmonious squad is the overriding factor for Martinez
Asked whether a new arrival could be imminent, he said: "We are close but it's not a matter of rushing things.
"We know exactly what we want and we will try to make it happen. If we can make it happen we just need to make sure the squad does not get affected by bringing the wrong personality to the club; that's very clear."