NFL's Marcedes Lewis -- NFL Could Fix Jameis Winston

Sure, he was a headache in college ... but the NFL could actually help Jameis Winston get his act together off the field ... so says Jacksonville Jaguars star Marcedes Lewis.

Lewis -- who's been in the league for 9 seasons -- was out in L.A. Wednesday and told us he believes in the various programs the NFL has in place to help provide "guidance" to young players.

"He's young. You expect him to make mistakes," Lewis said ... "The NFL, they have certain programs to help guide him through, so he'll be fine."

Of course, Winston decided to forego his junior season at FSU and declare for the upcoming draft because he's expected to be a first round pick.