Some English Premier League clubs have moved fast to fill their voids while others still haven't made a move.
Chelsea have solved their striking problem by picking up Demba Ba and Newcastle have finally pinched Mathieu Debuchy, but what of Everton and Southampton's needs?
One-third of the way into the transfer window, here are five EPL clubs still searching for the answers.
Ever since Ron Vlaar went down with a calf injury, Aston Villa have been visibly affected by his absence.
The Dutchman is the glue that holds Paul Lambert's side together, and with Richard Dunne a long-term absentee, Villa are down to the bare bones without cover.
Dunne seems set to leave in 2013 as his contract is set for expiry, so why not look for the solution now? In addition to centre-half, holding midfield could use an old head and the wings could house a new face, too.
If Everton escape January with all their key players intact they'll be happy, but they could really use another creative midfielder for the second half of the season.
Phil Neville doesn't cut it, and the Toffees were a completely different side without Darron Gibson due to injury—the Irishman is one criminally underrated player.
The race for fourth place looks incredibly tight, so January is best used to strengthen and go all out for UEFA Champions League football next season.
Queens Park Rangers may have picked it up a little in recent weeks, but even Harry Redknapp knows the squad needs some added quality.
Right-back is an area of concern considering how uncommitted to the cause Jose Bosingwa is, while the gaffer is currently trying to address the centre-back problem with a bid for Jonas Olsson being knocked back by West Brom (via BBC.co.uk).
The R's will hope for some success in the coming weeks.
Southampton are quite possibly one goalkeeper and one centre-back away from cementing their English Premier League status.
If they can conclude a deal for Cagliari's Davide Astori (via SkySports.com) then that's one down, but the search for a reliable goalkeeper is always a tough one.
If they're not able to sign a man to guard the sticks, the next best option is to pick a No. 1 and stick with him, rather than juggle between three or four options.
UPDATE: 15:41, Jan 11. by Sam Tighe
We're adding Reading in here, as they also belong on this list.
When I spoke to a Royals fan about their predicament, he lamented that Brian McDermott needed "11 new players."
While it's probably not as dire as that, some reinforcements are needed to stem the flow of goals. The manager has already made a great move in the transfer window by signing Daniel Carrico—a player who played UEFA Europa League football with Sporting last season.
He's versatile and confident and represents unbelievable value at £500,000, while Stephen Kelly could be coming in from Fulham (via SkySports).
McDermott has revealed his admiration for Danny Graham and Tom Rogic, two players who would help their cause significantly (via SkySports).