Arsenal v Crystal Palace (16:00 GMT)
BBC Sport's David Ornstein tells BBC Radio 5 live how midfielder Kim Kallstrom got injured, with Arsenal's new loan signing expected to be out for six weeks because of a back injury.
"Arsenal knew about the injury when they signed him, but they didn't know about it when he originally came to the club on Friday," says Ornstein.
"On Tuesday, after Mathieu Flamini was sent off, Arsenal realised they were short of numbers in midfield with Aaron Ramsey and Jack Wilshere out. On that same day, Kallstrom's side Spartak Moscow were at their warm-weather camp in Abu Dhabi.
"Kallstrom was playing beach volleyball and scored a goal and then felt discomfort in his back. An MRI at Arsenal did not reveal anything, but a CT scan showed the problem. Wenger said he would still sign Kallstrom and he would do his rehabilitation at Arsenal, instead of at Spartak Moscow."
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Wenger is an odd character at times as why show so much faith in an ageing midfielder? Makes no sense.