Autosport reports, not sure of the source, that Kovy was released by Renault because Fernando Alonso feared he represented too much of a challenge to him and wanted to avoid a repeat of last years Lewis Hamilton debacle.
‘It is understood that his speed ultimately cost him the chance of staying on board at Renault, because the returning Fernando Alonso did not want a team-mate to pose the kind of challenge that he faced with Lewis Hamilton at McLaren this year.’
I don’t know where the source came from but saying “it is understood” seems to be like the caveat “with all due respect” before telling someone they’re idiots. This may be true to some point but I think it is more than just being outclassed by rookies; Fernando is trying to recreate what Michael Schumacher did to win 5 titles. he wants a team built around himself with a supporting driver. If you can get that situation, why not?