Coming off a two-week international break, Arsenal fans probably hoped for a refreshed squad and the return of a few injured players. Instead, what they got was a calamity. Arsenal suffered a bad loss to West Brom Saturday and worse, a terrible addition to their already lengthy injury list as midfielder ­Francis Coquelin went down with a serious ­injury.

Coquelin is arguably the one person on Arsenal's squad - other than Alexis Sanchez, perhaps - who cannot be ­replaced. Manager Arsene Wenger said on the weekend that Coquelin's knee injury looked a "bit severe," and he is expected to be out for the rest of this year. Often an unsung hero, Coquelin's absence leaves a big hole, as his impressive defensive performances have stabilized and firmed up Arsenal's previous soft midfield.

Coquelin's replacement in the West Brom game, Mikel Arteta, is nearing 34 and is no longer as good as he was. It was sadly ironic Arteta also went off ­injured in that game. His replacement Matthieu Flamini is a warrior but, at 31, also aging and much more limited than before.

Not surprisingly, after hearing about the seriousness of Coquelin's injury, some fans quickly posted statements about giving up on the season or desperate pleas to God to heal Coquelin. At the rate that Arsenal players have been falling apart in the past month, almighty intervention might be the only thing that can save ­Arsenal.

Theo Walcott and Alex Oxlade-­Chamberlain were both injured in the same game in the end of October, while Aaron Ramsey suffered a hamstring injury on October 20. Danny Welbeck and Jack Wilshere have been out since before the season even began.

Arsenal have been running on fumes in the last few weeks, with Wenger ­desperately trying to fill in the holes and unable to rest Sanchez. They were barely able to keep up with Spurs in a battling draw on November 8 before the international break while being battered by Bayern Munich 5-1 the Wednesday of that week.

Coquelin's injury raises questions as to whether Wenger should have ­pursued another defensive midfielder in the off-season over the summer, as well as why Arsenal continue to suffer injury crises season after season. The upcoming January transfer window might see Wenger make a move to get a backup to Coquelin.

With a crucial Champions League clash against Dynamo Zagreb on Tuesday, Arsenal can ill afford to slip up, but sadly, it would not be a surprise if their weakened squad fail to win.

The author is a Beijing-based freelance writer. hcpyip@gmail.com