Presumably that means at least 15 league goals as Rom was excellent in the Europa and we got knocked out early in both cups so little scope for improvement there.To be honest, for 28m I'd have wanted a lot more goals than 20. I think we paid way too much for him, but I still thought he'd get around that many this season. He wasn't far off that last year after a spell out with injury, and a bit of a drought before the injury.
However there are only 5 players in the league this season that have scored that many (Aguero, Costa, Sanchez, Austin and Kane), even Rooney only has 12, 14 in total.