The pundit feels any Arsenal title challenge would be undermined by their back four.
Indeed, Laurent Koscielny and Mertesacker are the north London side's regular starters at centre-back.
Hoddle told the Mail: "I don’t think Arsenal are a title-winning team yet. But they have made significant progress in signing Petr Cech.
"To win the league you have to defend properly. Arsene Wenger was fortunate to inherit David Seaman, Lee Dixon, Martin Keown, Steve Bould, Tony Adams and Nigel Winterburn at the club. Then he created his own formidable back five in Jens Lehmann, Lauren, Sol Campbell, Kolo Toure and Ashley Cole.
"Since then, they’ve had a soft centre. Questions remain: is Gabriel strong enough? Will Per Mertesacker be consistent enough? But at least now they have a goalkeeper in the mould of Lehmann and Seaman."
During their Community Shield win, Arsenal demonstrated exactly what they haven't in recent years: defensive solidity.
And, as Hoddle suggests, a lot of that will be down to the impact of Cech in goal. Over the course of a whole season, however, it's fair to say Hoddle's concerns are valid.
Questioning Gabriel is interesting as the 24-year-old hasn't been given all that many chances by Arsene Wenger as of yet but has generally impressed for Arsenal. Mertesacker's decline in form in the past was notable, though, despite the fact he has looked better since Gabriel has come in to add competition.
But a title-winning defence...?