Napier is very inconsistent. When he's good he's phenomenal. When he's bad he's truly dire.
His 152 in a T20 against Sussex earned him an IPL contract but he's generally been very unlucky with injuries.
If he could find a level of consistency then maybe he'd have been selected. His T20 strike rate is good at just shy of 145 but he averages just 15.35 which is a sure indication of his inconsistency.