Former Liverpool striker Emile Heskey told IBTimes UK that Brendan Rodgers failed to address his side's defensive troubles earlier in the summer.
The Reds have endured a poor start to this campaign after finishing second in the last season. Following their 3-0 defeat at the hands of Manchester United, they now sit 11th in the table with 21 points after 16 games.
In addition to this, they were knocked out of the Champions League earlier this month and will now feature in the Europa League after finishing third in the group table.
Liverpool signed three defenders, Dejan Lovren, Alberto Moreno and Javi Manquillo, while allowing Daniel Agger leave Anfield in the summer. The former Southampton centre-back has struggled since making a switch to the Merseyside club.
They scored over 100 goals in the league and conceded 50 goals last season. Heskey believes Liverpool have failed to rectify their weakness of conceding and also failing to score regularly has seen them struggle this season.
"Liverpool have not got over [Luis] Suarez's departure and then you have [Daniel] Sturridge injured. They scored over 50 goals and also conceded 50 goals last season. If you go back over the years, I don't think any title winning team have conceded that many goals," Heskey told IBTimes UK.
"Then you go into another season with same problems, with not scoring as many goals as the last season. In addition to this, the Champions League football, where they had a chance to progress till the last group stage game against Basel. They haven't got the grips with the defensive rows and then they lost their firepower as well."
Heskey started his club career with Leicester City and he believes the Foxes should make additions in January in order to avoid relegation. They got promoted to the Premier League this season and Nigel Pearson's side now sit at the bottom of the table.
"Leicester have been defensively sound and everyone knew when they came to their home stadium during my time, they knew it's not going to be easy," the former England international said.
"And they showed similar character against their victory over Manchester United and also got the goals they deserved. Defensively Leicester haven't looked sound since then and attacking has been not great. But you got to have a strong base and defensively they have not been sound."
"I think everyone wants to invest in January regardless of where you are in the table and that is a necessity. So I will be surprised if Leicester does not spend in the mid-season transfer window," Heskey concluded.