By Tom Gott The manager of Portugal’s Under-21 side has revealed his shock at Fabio Carvalho’s abrupt refusal of a call-up. The Liverpool midfielder withdrew from international duty via text message earlier this week after failing to advance from the country’s preliminary World Cup squad to the final 26-player selection. Carvalho represented England between Under-15s and Under-18s but switched to Portugal in March, making four appearances for the Under-21 side before announcing his decision not to accept any further call-ups at that level. Whether he plans to switch back to England remains to …