The bottom line is that nobody will know until he has 20 starts /75+ PAs at a minimum. (Even that is probably less than sure) So let's get those out of the way before June. Then we can either be happy he's an Astro or kick him to the curb and bring someone else up or in.
He is a weird player - very good glove, with some power…. But his arm sucks, no one talks about how crappy a base stealer he is - and he blows hot and cold. He and Pena are the two bats I question. I think Abreu will end up hitting…. But his dry spells are annoying too.
Just go sign Brandon Belt and send Singleton to a dispensary where he can live his dream as a living blunt.