Liverpool keen on teenage Charlton defender Gomez

Joe Gomez has impressed in the Championship. Credit: PA

Liverpool are weighing up a bid for Charlton teenager Joe Gomez as a replacement for the soon-to-be-offloaded Sebastian Coates.

With Sunderland seemingly set to pay £4million to make Coates' loan last season into a permanent deal, the Reds are on the lookout for cover at centre-back.

Press Association Sport understands Gomez, aged 18, is of interest and while no formal offer has yet been made, the club believe there is a possibility of signing the England Under-19 defender for about £3.5m.

Liverpool currently have four senior central defenders in Martin Skrtel, Mamadou Sakho, last summer's £20m arrival Dejan Lovren and Kolo Toure.

Skrtel, who is out of contract in a year's time, is stalling over the terms of a new deal offered towards the end of last season while the 34-year-old Toure, whose new 12-month extension takes him to next summer, is not a long-term option.

Liverpool also have Tiago Ilori, a 22-year-old signed from Sporting Lisbon in 2013 but who has yet to make a first-team appearance and has spent loan spells at Granada and Bordeaux.

Gomez, whose breakthrough season in the SkyBet Championship last term saw him make 24 appearances, is viewed as a long-term prospect and - like Ilori - would more than likely be loaned out for more experience.

Liverpool are keen to strengthen their defence further with the addition of a right-back after Glen Johnson's contract was not renewed.

With a second knee operation ruling out Jon Flanagan until late in the year, manager Brendan Rodgers' current options are Spaniard Javier Manquillo, halfway through a two-year loan from Atletico Madrid but who failed to convince last season, and the 22-year-old Andre Wisdom, who has spent the previous two campaigns on loan at Derby and West Brom and has just signed a new four-year deal.

Brendan Rodgers has lost two members of staff. Credit: PA

A £10m bid for Southampton's England right-back Nathaniel Clyne was rejected late last month and as yet Liverpool have not returned with an improved offer, although the 24-year-old remains their main target for that position.

In terms of outgoings the club remain insistent Raheem Sterling, who turned down a £100,000-a-week contract in January, is not for sale after turning down a £30m offer from Manchester City last week.

Reports suggest City will return with an improved bid of £40m and while even that falls at least £10m short of Liverpool's valuation they are not of the mindset to sell the 20-year-old England forward.

They have adopted a similar robust stance to when Arsenal tried to lure Luis Suarez away with a cheeky £40m plus £1 bid in 2013 as Sterling still has two years left on his contract, despite his apparent unhappiness.

Meanwhile, the search continues to replace Rodgers' backroom staff after assistant manager Colin Pascoe was sacked and coach Mike Marsh did not have his contract renewed.

No appointments are imminent but with pre-season just three weeks away the process is expected to advance in the next fortnight.