I agree, Blum was useful but probably not at the price he was at. Erstad was done.
I do think Blum is more useful on a team that has a need for a player-coach and I'm not sure that team is the Astros any more. He had a bat you could count on and a fairly reliable glove, but I think the Astros are moving into a phase where they've got decent gloves available and they'll need to get untried players some time in the field rather than plug holes with a guy like Blummer. Best of luck to him and thanks for his fine service to Houston. He was definitely an Astro.