Although the Latics have at times this season looked like taking a major step forward, once again they find themselves embroiled in a dogfight to avoid the drop and slipped to a 3-2 home defeat by Sunderland.
According to Martinez, the reason is obvious. With Antolin Alcaraz missing almost the entire campaign so far with a calf problem and Ivan Ramis now ruled out for the remainder of the season following major knee surgery, the back three unit which proved so successful last term has been ripped apart.
It could not cope, with Steven Fletcher scoring twice to take his seasonal tally to 10.
The warning is clear. Unless Martinez finds a solution, Wigan's top-flight status will come under severe threat.
"What is clear is that we weren't strong enough defensively," said Martinez. "If Ramis had been on the pitch it would have been a very different situation.
"I need to make sure we rectify that and bring someone in who will give us the same strength Ivan was giving us.
"Antolin is still injured and we need to see how quickly he is going to be available because it is very unfair that the players who are here are having to cope with a lack of really good player alternatives for such a long period."