Rutledge is a fitness fanatic, so I'm less concerned about his age. The big thing is for him to get a full season and be healthy.
As for his performance, he's had a sub 5 ERA since July, with only two "bad" starts, and he's now put together four starts in a row with at least 5 innings and 3 or fewer earned runs. His strikeouts are up too. Wilmington's season ends on September 11. I think it would be worth it to send him there for the last month, just so he gets a feel for the place to prep him for next year.
We should also take his starts with a grain of salt. I've now seen him throw (either on video or in-person) four times in the last couple months. He's clearly using this time to work on a second fastball (sinker/two seamer) and his change up. He's taking a bit off of his fastball to work on location. I'm hoping its all coming together (or at least, he's trying) and this latest stretch is a result of that.