From another site-
Why I like Kevin Kiermaier, expanded edition:
1. he's not losing speed at the usual rate- at age 26-28, he averaged 29.3 ft/s; at age 29-32, he averaged 29.3 ft/s, including 29.2 last year. He was the 7th fastest player of his age at age 28 and he's been the second fastest of his age the last 2 years
2. I don't buy the 85 wRC+ projection; he has a 97 wRC+ over his career and it was 94, 101 and 90 over the last 3, and his xwOBAs over the last 3 years were almost exactly his career average
3. he's been a fabulous baserunner over his career, and the metrics suggest that he has lost nothing in that regard
4. there is the promise that the surgery will improve his functioning for a year or three; the hip has been a lingering issue.
5. last year, Kiermaier had a 5.0 IFFB rate and a 17.5 % HR/FB rate; it's the first time a ball in the air was an effective weapon for him; I don't think it's beyond the realm of possibility that he blows by his personal bests entirely and becomes one of the very few players who is considerably better at age 35 than at age 25.