Glaus is slugging 155 points better on grass this year vs. on turf (.533 vs. .388). His turf numbers are inflated by the period in April before he got put on the DL for the aforementioned spurs. Since April he's slugging .326 on turf vs. .543 on grass.
It's clear playing on turf this year is killing him, but his numbers on grass are still good enough that someone will want him. The question is whether his heel spurs will be better next year. Since the usual treatment is orthotics, they either haven't got him some yet for some reason (which would be dumb unless it's a really good reason), or they did and they're not working. If they're not being stupid, this problem may be back next year, which would not be a good use of $13M (not to mention the almost $4M he's due for the rest of this year). At least it's unlikely that he would exercise his option to keep playing on a surface that causes him pain, but being weak offensively and defensively in the hot corner while spending all that money could cripple the team next year, no pun intended. I'm against trading Glaus as a pure salary dump, but considering that we could get a player or players for him that would play well on turf, we may need to deal him. I'd even consider playing Stairs at third for the rest of this year, just to keep his bat in the lineup.