If anyone knows a thing or two about defending, it is former England and Liverpool man Carragher, who spent 17 years at Anfield and played at two World Cups for his country.
His issue with both Manchester United defenders is that they don't yet know whether they are best suited as centre-backs or right-backs. Finding out, the ex-Reds man believes, would be best done sooner rather than later.
Giving his verdict on England's current World Cup squad, Carragher wrote in the Daily Mail: "He’s not had a great season at Manchester United.
"He’s had the same problem I had early in my career — playing in several positions means it is hard to nail down a regular starting spot. It took me until I was 23 or 24 to settle on being a centre back and Jones, at 22, needs to do the same now."
And of Smalling, the 36-year-old had a similar, albeit more positive take: "He’s someone Hodgson knows well and trusts from his Fulham days. Like Jones, he has struggled this season and we’re yet to find out if he’s a central defender or a right back. Could be asked to fill in if anything happens to Glen Johnson."
|Team||Aerial Duels Won/ app||Costly Errors/ app||Interceptions Won / app||Effective Clearances / app||Tackles Won / app|
|Chris Smalling||Man Utd||2.52||0.04||1.04||7.12||1.20|
|Phil Jones||Man Utd||2.08||0||2.12||5.73||1.69|
Indeed, Opta stats back up Carragher's claims to a degree. Though Jones and Smalling did not endure a catastrophic season individually last term, they were far from their best in a Manchester United side that ultimately finished seventh in the Premier League.
Both defenders were less convincing than their England team-mates in the air, while each of them lingers behind in certain areas (apart from tackles won per game, which suit both well).
So does Carragher have a point? Are Smalling and Jones' struggles down to the fact that they play two different positions - and should they choose one and stick to it?
Perhaps the pair could agree between themselves and choose one each. As Carragher points out, England would benefit from Johnson being pushed at right-back, while cover at centre-back for Gary Cahill and Phil Jagielka would be more effective were it to come from a specialist in one position.
At club level, meanwhile, a similar approach would no doubt help solidify Louis Van Gaal's back four at a crucial time in United's development.
With both Nemanja Vidic and Rio Ferdinand having left the club this summer, the 22-year-old Jones and 24-year-old Smalling will have to stand up and be counted.
The alternative is a fall down the pecking order...and that goes for their England places, too.