1
...your argument shouldn't have been "are there players who have good years at 25/26 and then disappear for ANY reason?" but "Are their players who have good years before 26 and then lose their skill for playing baseball without any particular reason?" The answer is STILL yes. E5 Hinske, Angel Berroa, Adrian Beltre...of the top of my head...had career years before 26 and never reappeared at that level.