Yes, I recall the Matt Jones experiment.
A team with an aging QB might want to bring in someone like LJ and groom him for the QB position---in the meantime, work him into the roster as a WR while he learns the system, acts as the backup QB.
The big knock against LJ is his frail body and his accuracy---might be able to work on both with him as a backup QB and earning his roster spot playing WR.
Cards brought in Tom Tupa who played both QB and was also a kicker---the QB role didn't work at the NFL level but he turned into a decent punter and played in the league for years.
this is a myth. there is no evidence to suggest Jackson is frail. He is thin, but his weight would indicate that he is thin due to an extremely low body fat.
Sam Darnold 6'3 1/2" 221 lbs
Lamar Jackson 6'2 1/4 216
Josh Rosen 6'4" 226lbs
Andy Dalton 6'2" 215 lbs at combine.
The only reason Jackson "looks" smaller is because the kid is solid, muscle weighs more than fat....
nobody is knocking Darnold for his height/weight ratio and Andy Dalton has played QB in the NFL without getting killed.
Lamar Jacksons height/weight ratio is right in their with other top QB's... the only way his size really comes into issue is if a team plans to use him like Cam Newton was used in the early years... thats a mistake. if an nfl team drafts him as a QB they need to treat him like a QB...keep him in the pocket, passing the ball...and using his mobility to escape pressure so he has more time to throw...much like
Russell Wilson 5'11" 204 lbs
or
Jake Plummer 6'2" 195lbs