Merrington has no doubt Oxlade-Chamberlain will follow former Saints youngsters Bale, Alan Shearer and Theo Walcott by progressing into one of the best players in England.
"Out of all the players I've seen over the years he's going to be up there with the Shearers and the Walcotts and the Bales," former Southampton manager Merrington told talkSPORT.
"He's got lightning pace, he's got quick feet and for 17 years of age he's very mature. He's got a very good football brain.
"Every so often you get a boy who comes through the ranks, they jump through the reserves and into the first team and never look back and this boy is terrific.
"Rodney was a terrific player, he could play either flank, he could play down the middle and this boy is exactly the same. He drifts off the flanks, he finds himself in striking positions and he scores goals."