Trading Skubal concerns me for two reasons:
1. (The obvious one) Al Avila would be doing the trading
2. While we do not know whether he grows into it, he's the pitcher in the system most likely to achieve ace status.
With respect to the second point, I do think the Tigers have become a decent org in terms of developing pitching talent, but if we are completely honest with ourselves, outside of Skubal, who is the guy that they have who can grow into a 1 or a 2 starter? Maybe Madden imo, but even with him I'm skeptical.
Assuming Manning doesn't get there, they have a bunch of guys who currently project, best case scenario, no higher than a 3 (ie. Faedo, Brieske, Olson, Hill etc.). And then you have complete wild cards in Turnbull and Mize... what do they look like if/when they get back? Probably not front line guys
There's always a price, so I guess if you could get someone like Alec Burleson or Nolan Gorman off the Cards, maybe it becomes worth it. But I doubt that's happening. So I hope they don't move him.