We simply must stick with Sodhi.
He is already "probably" our best test spinner (evidenced by no real alternatives - and no, I do not see Vettori as an alternative, even if he did become fit) AND, most importantly, is the potential with him is something we have not seen since christknowswhen. Yes he's young, inexperienced, has a lot to learn... but he will only learn by playing. As much as I'd love him to have a year or two in county cricket, even if he did that he would be more likely to be underbowled than anything else and as long as Hesson and McCullum keep behind him then hopefully in 2-3 years time he'll flourish... and we'll have a world-class spinner for a decade or more!
And, he can hold a bat too.