Andy Robertson’s return to Anfield for the Carabao Cup has brought attention to Liverpool’s ongoing struggles in the left-back position since his departure. Robertson left the club in the summer, and his absence has reportedly weakened the team’s defensive structure on the left side. His return has been quick, possibly within four months of his exit, contrasting with Jordan Henderson’s four-year wait for a similar reception from his former club. Despite the expected warm welcome, Liverpool may already be feeling the effects of his departure. Robertson’s recent performance against Everton, where he played a key role in keeping a clean sheet, contrasts with his benching at Nottingham Forest the previous week. Early signs from Anfield suggest that Liverpool’s left-back department has been weakened since Robertson’s exit. His replacement has been Kostas Tsimikas, who returned from a loan at Roma to act as Milos Kerkez’s understudy. Tsimikas made his first start for Liverpool in 15 months on Saturday, but he was substituted after a lackluster performance. Kerkez, who had appeared as the weakest link in the previous match against Atletico Madrid, showed some improvement, indicating that Tsimikas may not be the long-term solution. Andoni Iraola, the new manager, may need to rotate the left-back position due to the potential for a 60-game season, his hard-running style, and the attacking demands on full-backs. Last season, Robertson started 20 matches in all competitions, which may have been too few considering Kerkez’s struggles in his first few months at Anfield. It is harder to see Tsimikas starting 20 matches now, even though he has started 19 for Liverpool on two occasions. Competition for the left-back position feels more important than in other parts of Iraola’s squad. Kerkez has been at fault in crucial moments, with two goals conceded directly from his defensive errors. Liverpool have conceded five goals so far this season, with two coming from Kerkez’s immediate opponents. Jeremie Frimpong’s evident failings in the first couple of weeks of the campaign meant Kerkez was not the biggest problem initially. Iraola has seemingly solved the right-back conundrum by bringing in Ronald Araujo for Frimpong. However, there is no such obvious fix on the left. A match-up with Rayan, the precocious Brazilian brought in during Iraola’s reign, promises to be challenging. A comparison with Adrien Truffert, the left-back signed as Kerkez’s successor, could be unflattering. Each made a Premier League debut for their new clubs in the same game 13 months ago, with Truffert looking better than Kerkez in that match. Kerkez’s youth offers potential for improvement, being almost a decade younger than Robertson and two years younger than Truffert. A reunion with Iraola, a manager whose tactics should suit him more than Slot's ever did, is another reason to back Kerkez as the long-term choice. However, they could benefit from seeing performances to support that backing. Kerkez was better in the second half of last season, without being fully convincing. When Robertson confirmed he would leave when his contract expired, it soon emerged that Tsimikas would return and that Liverpool would not go into the market for a left-back. They had greater priorities, needing to save the budget for wingers. They were looking for Tsimikas to buy them time. Next summer, too, there could be plenty of other positions that require addressing. Replacing a player of Robertson's stature was never going to be easy, and Liverpool have not found the right replacement in two roles: either as the first-choice left-back or the reserve.