Bartley rates the pairing as the most powerful in the Premier League.
"There is some real muscle there, it's very hard training against them but it is also a great test and if they are paired up then there is no defence they will not cause problems for," 6ft 4in centre-back Bartley told WalesOnline.
"I don't think I could pick a more difficult pairing in the Premier League. I think working with and against them in training can give us a fantastic edge when the season starts.
"Because they will cause anyone problems. They are two flexible guys who can work off each other and it will help the team develop different styles of play."
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