BBC Sport looks at Liverpool's issues at centre-back, and what Andoni Iraola might do to fix them.

Two centre-backs caught the eye of Liverpool's scouting department at the U17 World Cup in Qatar last November. Within weeks, the club spent a combined £3.5m on the pair: Senegal's Mor Talla Ndiaye and Austria's Ifeanyi Ndukwe. Under Matt Newberry, Liverpool's director of global talent, this was evidence of future planning in full flow. Yet surely no-one inside the club would have expected the teenage duo to be the centre-back pairing for most of Liverpool's opening pre-season fixture. With Joe Gomez forced off by injury in the eighth minute against Sunderland, and neither Jeremy Jacquet or Giovanni Leoni fit to play still, Liverpool have a problem at the heart of their defence. Looking at the long term is one thing, but they need reinforcements in the here and now. Even before the injury, new head coach Andoni Iraola said his squad was "very thin" defensively. Gomez was absent from Liverpool's training session in Chicago on Sunday and an update on the severity of his injury is expected this week.