Liverpool have won just once in their last six games in all competitions and that came in an FA Cup replay against Plymouth.
And Saturday’s 3-2 defeat to Swansea leaves the Reds ten points behind runaway leaders Chelsea.
Liverpool training ahead of EFL Cup semi-final
Tue, January 24, 2017
Click through the gallery for the best snaps of Liverpool in training
Liverpool FC via Getty Images
1 of 11
Click through the gallery to reveal which Championship stars have committed more fouls than anyone else this season
Liverpool have a chance to get back to winning ways on Wednesday when they face Southampton in the second leg of their EFL Cup semi-final.
But Thompson is concerned Liverpool’s lack of strength in depth has been exposed.
Jurgen Klopp will attempt to rally his team ahead of their EFL Cup semi-final
He told Sky Sports: "We haven't got as big a squad as people make out. Klopp has probably got 14 or 15 players he really trusts and we had three or four very young players on the bench on Saturday.
"Key absences have exposed that. I think it all started when Philippe Coutinho got injured. I know people are pointing to Sadio Mane's absence but Coutinho's relationship with Roberto Firmino is extra special.
Phil Thompson feels Adam Lallana's form has dipped recently
"I think Firmino's form dipped a little bit, and even Lallana, who is our main go-to player has looked a bit tired.
“All the high intensity that Klopp's sides play combined with the heavy workload has resulted in general a dip in form."