Waddle questioned the transfer activity of Tottenham manager Mauricio Pochettino on Friday, arguing he did not improve the squad at White Hart Lane and was remiss in not signing a central defender.
Of the six players Pochettino signed heading into the 2014-15 season - after arriving himself from Southampton - only Eric Dier has started in the Premier League.
"I don't think they've had a good pairing at centre-half since Ledley King played," Waddle told the Evening Standard.
"Every game I watch Tottenham play, [Hugo] Lloris seems to be called into action every two or three minutes, so there's got to be a problem if you're goalkeeper makes too many saves."
Waddle thinks Tottenham's defence is holding them back with Pochettino's men sitting sixth in the league ahead of Saturday's clash with reigning champions Manchester City.
"If they can sort out the back two there is no reason they can't challenge [for the top four]," he said.
"I think he's [Pochettino] got a lot of players very similar to what was already there, there are a lot of players who can play the same role," Waddle said.
