Bo Jackson knows firsthand how injuries can evaporate careers.

So it comes as little surprise Jackson backed up Fox Sports football analyst Troy Aikman's evisceration of FS1 personality Doug Gottlieb, regarding Gottlieb's comments in the hours after Andrew Luck announced his retirement from the NFL.

"Retiring cause rehabbing is 'too hard' is the most millennial thing ever," Gottlieb tweeted Saturday night. Aikman responded with a scathing critique on Twitter the next day, which Jackson supported Monday.

"I stand behind @TroyAikman and every word he said," Jackson tweeted. "Don't criticize a man until you've worn his cleats. If you've never strapped on the pads you have no business commenting on something you know nothing about."

He followed that up with a show of support for Luck himself.

Luck retired Saturday night, citing the physical toll from various rehab processes he's endured over the last few years of his career.

Jackson's football career was cut short after he suffered a hip injury in 1991 with the Oakland Raiders, which also effectively ended his baseball playing days.

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