My alternate fandoms don’t really play into this, as I had enormous frustration over Mauer who was both better and descended more rapidly than Yelich, also immediately following a severe injury.
But they’re both human beings who reached the absolute pinnacle of achievement while we’re just fans. No one, and I repeat no one, is more frustrated with them than themselves.
It’s an important thing to keep in mind.
Be disappointed, be frustrated. Feel your love of the team. But remember, that formerly great player feels it more deeply and intensely than you or I ever will.