You got any evidence for this theory Tom? Genuine question.
because nothing I heard, read or saw corroborated this. Onomah was training with the first team for three years and in that time got 20 minutes of PL football, and 3/4 starts as a winger (he's a CM). Then the final straw came after he was one of the best players when England won the U20 WC, Poch took him on the pre season tour and played TAB in CM and Onomah as a winger again. I think he begged to go on loan because he was just desperate to play football.
Personally I wish we'd kept him here and Poch had shown the patience and indulgence with him that he did with Sissoko, let Onomah stink for two seasons if necessary, and we might have a midfielder who can play football by now and saved ourselves 55m in fee and wages.