Joe (born 15 May 1990) is an English semi-professional footballer who plays as a left-back for National League North club Marine.
Mattock spent three seasons with Sheffield Wednesday before moving to fellow South Yorkshire side Rotherham United.
Mattock was a regular for the Leicester under-18 side (playing alongside the likes of Ashley Chambers, Max Gradel, Andy King and Eric Odhiambo) as well as England U17s.
He made his senior debut for Leicester in a 2–1 home defeat to Norwich City on 14 April 2007, replacing Gareth McAuley in the 78th minute at left back.
[7] Mattock suffered ligament damage to his left ankle in a 1–0 League Cup win over Stockport County on 12 August 2008.
[8] On 28 August, three days before the close of the transfer window, Leicester rejected seven-figure offers from two unnamed clubs for Mattock.
[7] He signed a three-year contract with West Brom four days later for a fee of £1 million, citing Richard Stearman as his motivation for leaving Leicester.
[14] In January 2011, he joined Sheffield United on loan until end of the 2010–11 Football League Championship season[15] making his first start for the Blades away at Coventry City a couple of days later.
In November of the same year, Mattock joined Championship team Portsmouth on a loan deal lasting until 2 January 2012, alongside George Thorne.
[17] On 31 January 2012, Mattock signed for Championship side Brighton & Hove Albion on a loan deal lasting until the end of the season.
[20] In June 2012, Mattock was expected to complete a permanent transfer to Brighton following his successful loan spell, but instead agreed a three-year contract at newly promoted Championship side Sheffield Wednesday.
[40][41] In July 2011, Mattock pleaded guilty to a charge of affray and on 23 October 2011 he was sentenced to ten months in prison, suspended for two years, and ordered to complete 150 hours of unpaid work and pay £1,500 costs.