Former Arsenal star, Theo Walcott, has urged manager Mikel Arteta to replace William Saliba with Riccardo Calafiori at centre-half against Liverpool next weekend when both teams clash in the Premier League. Walcott said he is worried about Liverpool winger Mohammed Salah’s space against Calafiori. He made the demand after Saliba was shown a straight red card on Saturday night as the Gunners fell to a 2-0 defeat at Bournemouth. The France international is now set to miss Arsenal’s three Premier League fixtures against Liverpool next Sunday followed by Newcastle United and Chelsea marches. “I wo…