You're kind of reinforcing the point though -- now you've got a whole team distracted by picking up a new language....why? how is it a good use of anyone's time? And it'll be a perennial training issue in the case of an esoteric language, because those team members will eventually turn over as well, meaning that you don't get to avoid either hiring or training a new person on it.
If it's just one component, implemented by a single dev, it really can make more sense to understand what it does and rewrite it in a language that's common in the company.
I'm not advocating NOT rewriting it. I'm just saying, back to the great grandparent's point, that the issue is a dev went rogue, NOT the language the rogue dev chose. The difficulty is the same regardless of the language the rogue dev chose; it's not that they picked Clojure, it's that they picked a language there was no organizational adoption of.
If it's just one component, implemented by a single dev, it really can make more sense to understand what it does and rewrite it in a language that's common in the company.