Former Chelsea midfielder Emmanuel Petit has sharply criticised the club's American owners for treating the team purely as a business. Amidst defensive struggles and four consecutive defeats, Petit warns that new manager Liam Rosenior may not see out the rest of the season, demanding an immediate change to salvage their fading Champions League qualification hopes.The mood at Stamford Bridge is darkening following a dismal run of four consecutive defeats. Since taking charge in January following the dismissal of Enzo Maresca, Rosenior has overseen 19 matches, but his honeymoon period is well and truly over. Recent heavy losses include a 5-2 away defeat and a 3-0 home loss to Paris Saint-Germain, which saw them crash out of the Champions League in the round of 16. Following the weekend's 3-0 Premier League defeat at the hands of Everton, they sit sixth in the table on 48 points. They are now six points adrift of fourth-placed Aston Villa, severely complicating their European qualification chances.According to Petit, the main issue plaguing the London side is their fragile backline, as he told BetGoat: "The main trouble at Chelsea is probably the defence. They have many, many issues, but the main problem is the defence. They concede too many goals. They have lost too many games at home and are probably one of the most average teams at home in the Premier League. I think they are 12th or 13th in the table at home." Replacing Maresca has proven difficult, with the Frenchman adding: "I think the dimension of Strasbourg fit perfectly with Rosenior. Giving him the responsibility of such a huge club like Chelsea is a huge step, especially after taking charge after Enzo Maresca left the club."The former midfielder directed fierce criticism toward the club hierarchy, suggesting they prioritise commercial interests over sporting triumphs. Delivering a scathing assessment, Petit declared: "I have no idea if he's going to stay at the end of the season, but to be honest with you, something has to change. I think the American owners must understand that we respect, and I have huge respect for those who put the money on the table, but in the end, don't put your nose in matters that you don't understand." He insisted that treating football strictly as a business is alienating supporters. "Football is a serious matter for so many people, and you are trying to make business all the time, which means the Chelsea fans are tired of it. They don't want business at the club, they want success."Add GOAL.com as a preferred source on Google to see more of our reportingThis lack of direction is seemingly taking a psychological toll on a mentally exhausted squad. Petit questioned the overarching strategy, asking: "Starting from the start of the season, what is the vision in terms of sport as well, with the manager? What is the vision? How are we going to play?" This was brutally exposed against PSG. Petit was baffled by the managerial decisions, stating: "When you look at Rosenior against PSG and they played three at the back, come on. Have you seen against which team you're playing? Who are the strikers at Paris Saint-Germain? Those guys, they kill you. One against one, they kill you. And you play three at the back? Really?"