Arsenal go into Sunday’s London derby against Chelsea with significantly more injury concerns than their opponents -- a fact that shouldn't surprise anyone given the contrasting fitness records of the clubs’ squads in recent times. A report by Premier League injury compilers has revealed that Arsenal have suffered 889 injuries in the last 12 years, significantly more than any of the other big Premier League teams. Chelsea have sustained just 620 in that time by comparison.

The injury crisis Arsenal currently find themselves in then is an all-too familiar scenario. Ahead of the clash between the two title challengers at Stamford Bridge, Arsenal have eight players unavailable -- defenders Mathieu Debuchy (ankle) and Nacho Monreal (back), midfielders Mikel Arteta (calf), Aaron Ramsey (hamstring) and Serge Gnabry (knee) and forwards Olivier Giroud (ankle) and Theo Walcott (knee). Walcott, alone, has suffered 42 separate injuries since 2006. Abou Diaby has just returned from his 40th injury but is still not fully fit and Kieran Gibbs young career has been blighted by injuries, numbering 27 since 2009.

So regularly have Arsenal found themselves shorn of a number of key players and perched high up on the Premier League injury table that in the summer manager Arsène Wenger overhauled the club’s fitness strategy. The appointment of Shad Forsythe, a fitness coach for Germany during their 2014 World Cup triumph, highlighted Wenger’s attempts to address the recurring problem. Yet ahead of the win over Galatasaray this week he conceded that he remained short of answers.

“We made a lot of changes, yes,” Wenger said, according to The Guardian. “We have made changes in the way we prepare, in the way we work on prevention for injuries. When you work on the prevention for injuries, it’s a question mark: ‘Why do you get the injuries?’ We know a lot more than 18 years ago when I arrived but still not enough to predict 100 percent scientifically what happens to everybody.”

One possible cause that Wenger will be loathed to countenance is that the volume of injuries has been increased by his failure to build squads strong enough to make resting key players palatable. Last season Wenger neglected to buy an adequate alternative to Olivier Giroud, who played more than 50 games and clearly faded physically toward the end of the campaign. Wenger allowed this summer’s transfer window to close with just six senior defenders in his squad -- including 19-year-old Calum Chambers. They now only have four fit and available and thus no room for rotation. Wenger has admitted in the past that his overuse of players may have contributed to an injury.

“We knew he was in the red in the last two months and we continued to play him because we had no choice,” he said of Jack Wilshere in 2011. “But maybe it is a consequence of the overuse last year.”

That injury for Wilshere was indicative of another of the issues surrounding Arsenal’s injuries. It is not just the frequency of them but the length of the recovery times. Wilshere’s initial prognosis in the summer of 2011 was that he would be out for a matter of weeks. He didn’t play again for 15 months. It was a similar scenario with Aaron Ramsey when he suffered a thigh injury last December. Having been initially predicted to miss three weeks, the Welsh midfielder ended by being absent for three months. Wenger has spoken of his concern this week about Ramsey’s hamstring problem, which, currently, is expected to keep him out for four weeks.

Chelsea have rarely had to deal with such a proliferation of injuries and the Premier League leaders head into Sunday’s showdown with only Ramires and Didier Drogba unavailable. The major concern so far this season has been the fitness of prolific new striker Diego Costa. Having been troubled by a hamstring injury at the end of last season with Atletico Madrid, the Brazil-born Spain international suffered a recurrence while on international duty last month. Manager Jose Mourinho has since lamented that Costa could not play two games in a short space of time, but, after playing in the 3-0 win over Aston Villa on Saturday, he started Tuesday’s victory at Sporting Lisbon. Speaking ahead of the Champions League clash in Portugal, Mourinho accepted that starting Costa jeopardized his availability to take on Arsenal.

“There is a risk, yes, but he plays,” he said, according to Chelsea’s official website. “We assume the risk and he plays. Hopefully everything goes well and hopefully from Tuesday to Sunday he has enough period of time to be back on track and play against Arsenal.”

But, having played the full 90 minutes in midweek, Costa is in no doubt that he can line up against Arsenal. “Of course I will play against Arsenal. I am certain,” he said, reports the Daily Mirror. “I played 90 minutes [in Lisbon] and now I can have a rest. I do not see a problem. “There are a few niggles that are annoying me, but I am working to treat them during the week with the physios and the medical staff. Every day I feel closer.”