Arsenal manager Arsene Wenger conceded not reinforcing his depleted defence before the close of the January transfer window would be too "risky".
French full-back Mathieu Debuchy added to Wenger's defensive woes during the week, ruled out for three months due to a dislocated shoulder.
Arsenal's defensive stocks have been tested throughout the 2014-15 Premier League season, with Laurent Koscielny, Kieran Gibbs and Nacho Monreal all spending time on the sidelines.
West Ham defender Winston Reid and Borussia Dortmund captain Mats Hummels have been touted as potential signings in January.
And Wenger is aware failure to add defensive cover would be a gamble with Arsenal desperate to qualify for next season's UEFA Champions League.
"It's risky. It's too risky," said Wenger. "If we have another injury or two we will struggle.
"We can, because we have [Calum] Chambers, [Per] Mertesacker, Koscielny. But we have now lost Debuchy, who could play centre-back, Monreal, who can play centre-back, Gibbs as well has been out.
"Of course we have made enquiries and then you have a second handicap of who wants to sell their best players, especially a central defender, in the middle of the season.
"They say: 'OK, come back in June or July and maybe yes.'"
Wenger added: "I am not the only one working on the case."
"It's not a supermarket where you go in and buy a defender, it's a market that is very restricted, that players who can strengthen the best 10 teams in Europe, you don't find many and it's the same for everybody.
"We are a big attraction, of course we are, but if it was easy we would do it."
