"I'm a big believer that playing for the Under-21s gives you good grounding for your career," BBC Sport quotes Armfield as saying. "Tom will need that if he's to follow in Paul's footsteps.
"Playing international football is a nice distraction to have from the domestic campaign. Stuart Pearce has done reasonably well in charge of the Under-21s and I'm sure Tom will be looking forward to working with him and the team of Football Association coaches.
"Sometimes it's nice to hear a different voice in training, or practice with players from other clubs as you can learn so much."
Armfield spent all of his club football career at Blackpool and played for England between 1959 and 1966.