Liverpool's injury crisis has deepened in recent days, as Joel Matip and Fabinho joined the likes of Virgil van Dijk and Joe Gomez on the treatment table. While Jurgen Klopp admitted that both his players could return to the side in a week, reports have emerged that the Reds could sign two central defenders before the January transfer window slams shut.With less than a day to go before the deadline, Liverpool face a race against time to complete their transfer business. The reigning Premier League champions defeated West Ham 3-1 with an unlikely central defensive partnership of Nat Phillips and Jordan Henderson, with Rhys Williams on the bench as a backup.With the UEFA Champions League knockout stages and the business end of the Premier League season on the horizon, Liverpool are looking to bolster their rearguard to stand a chance of competing for both titles.Here are five defenders they could turn to on deadline day to ease their central defensive injury woes.Ben Davies, DCC, Merih Demiral, Mustafi, Diop#5 Ben Davies | Preston North EndBirmingham City v Preston North End - Sky Bet ChampionshipAlthough it's not official, it has been reported by various sources that Liverpool have agreed a deal to sign Ben Davies from Preston North End. The Englishman is in the last six months of his contract and is on the verge of joining the reigning champions for a fee believed to be in the region of £2 million.Liverpool have now agreed a fee in the region of £2m with Preston for Ben Davies. Sepp van den Berg moving on loan.— paul joyce (@_pauljoyce) January 31, 2021Davies has been described as an excellent reader of the game by those who have watched him, while his ability to go toe to toe with strikers bigger than him has also been mentioned as a feature of his gameplay. The 25-year-old is expected to have his Liverpool medical later in the day, as he looks set to complete an unlikely move to the Merseyside giants.#4 Shkodran Mustafi | ArsenalArsenal FC v Norwich City - Premier LeagueShkodran Mustafi is a household name in the Premier League, having been on the books at Arsenal for quite a while now. The German international has often been slated for his error-prone nature and is currently out of favor under Mikel Arteta, as he enters the last five months of his contract.Arteta on Mustafi and others leaving before the end of the window: "There are some conversations going on at the moment. The club is willing to help some of them, whether we find a solution or not, I don’t know."— Charles Watts (@charles_watts) January 30, 2021The 28-year-old is a far from ideal solution at the back for Liverpool, but the Reds are in desperate need of reinforcements and could well turn to him if they fail to land their top targets.