Wigan manager Roberto Martinez admits he needs to strengthen his squad in January after recent events left him short of cover.

Left-back Maynor Figueroa's knee ligament injury has ruled out the Honduras international for two months while Marlon King's sacking after receiving a prison sentence leaves the Latics boss a short of a striker.

King's departure will have a lesser impact as he played just 14 minutes in three Premier League substitute appearances as Martinez has opted to play one up front this season.

Figueroa's lay-off allowed Erik Edman to make his first league appearance since last May but there is no other recognised left-back in the squad.

Former Manchester City and Everton defender Michael Ball, currently out of contract, has been training with the club in a bid to improve his fitness but is not seen as a viable option to cover Figueroa's absence.

The situation has highlighted to Martinez the issues he has to address when the transfer window re-opens.

"We need to strengthen, as we have lost a player (Figueroa) and cannot leave ourselves open," said the Latics boss.

"We know our budget, the money we have to spend, but it is not just about that.

"It is about finding the right players and personalities. We will work on different markets to try to make things happen."

Martinez has been in his first Premier League job less than six months but knows he has to put in place foundations which will serve the club better over the coming seasons.

"If we are missing two or three players, we are going to be affected," he told the Wigan Evening Post.

"It's something that doesn't concern me but it's something we need to look to address over the next two or three years, and come up with a stronger structure."