Who Arsenal could turn to
Gary Cahill (Bolton Wanderers)
Probable cost: £15m
Who he replaces: Laurent Koscielny
Why he is needed: Koscielny is a good prospect and his rise has been rapid, but Arsenal need a dominant centre-back with Premier League experience who can play alongside Thomas Vermaelen.
Panic rating: 4/5. As ever in recent years, it is the defence at Arsenal that remains the most urgent priority.
Marvin Martin (Sochaux)
Probable cost: £12m
Who he replaces: Cesc Fabregas
Why he is needed: Arsenal lack creative players who can fill a central playmaker role after the departures of Cesc Fabregas and Samir Nasri, but Martin is a promising France international in a very similar mould.
Panic rating: 3/5. Arsenal have options in this position, but Aaron Ramsey still looks better in a deeper-lying midfield role while Andrey Arshavin and Tomas Rosicky continue to flatter to deceive.
Park Chu Young (Monaco)
Probable cost: £3m.
Who he replaces: Nicklas Bendtner
Why he is needed: Robin van Persie is no stranger to injuries but, with Bendtner still hoping to leave and Joel Campbell waiting for a work permit, the only cover in attack is Marouane Chamakh.
Panic rating: 5/5. Arsenal clinched the deal for Park ahead of Lille by a matter of hours, with the French club even understood to have paid the costs of a hotel room for a player they expected to sign.
Yann M'Vila (Rennes)
Probable cost: £25m.
Who he replaces: Denilson
Why he is needed: How often has it been said that Arsenal require a midfield enforcer? M'Vila is regarded as one of the best and is priced accordingly, but the past few weeks have underlined Arsenal's dependence in that position on Alex Song.
Panic rating: 3/5. Rennes have already knocked back one inquiry and Arsenal would probably need to break their transfer record to secure M'Vila's signing.
Phil Jagielka (Everton)
Probable cost: £17m.
Who he replaces: Sebastien Squillaci
Why he is needed: With the exception of Vermaelen, there are doubts over all of the Arsenal centre-backs. Jagielka would add extensive Premier League experience and, with Cahill, would provide deeper options in defence and allow Vermaelen to play at left-back.
Panic rating: 3/5. Arsenal have bid for Jagielka in each of the last two summers and not been close to Everton's valuation. An acceptable offer would underline the urgency of the current situation.