Tavares is on-loan at Lazio from Arsenal, but his permanent transfer is a formality.
Martinez said, "The aim is to continue the work started in September and October, forming a larger group. Having 26 players helps, the November period is always difficult. The idea is to win, get the 6 points up for grabs and grow."
On Tavares, he said:"He has a particular physique and characteristics. He is very interesting."
Martinez also nominated Wolves striker Fabio Silva, currently on-loan with Las Palmas, as a potential heir to Cristiano Ronaldo.
He said, "It's a challenge in Portuguese football, finding another striker. It's a profile that is obviously not easy to find. There are players like Fábio Silva and Tiago Tomás, who are growing a lot. If we want to grow as a team, we have to show that we can score goals with other players and that's the work we will do at this stage.
"We have many virtuous and quality players, but we have to understand who can finish. Cristiano Ronaldo is our striker at this stage, but there are other players, there are many players. The competition in attack is not a problem, I'm not worried."