I'm one of the bigger Vereen fans/optimists on this forum, I think, but I wouldn't even think about extending him unless it was for way below his healthy market value. He needs to stay healthy for a season before you can give him a long-term extension, and in the likely event that he misses games this year, he should be pretty cheap in the offseason.
If he's willing to sign for very little long-term, then sure, but that wouldn't make a lot of sense for him. He might as well play out this season, and make a lot more money if he can stay healthy.