Ex-NFL star Jamal Lewis says Tua Tagovailoa needs to be very, very careful with his health going forward after suffering a concussion last week ... telling TMZ Sports effects from similar head injuries that he's experienced in the past have lingered "for years."
"This is a silent creeper," Lewis said of post-concussion symptoms, "that can haunt you for the rest of your life slowly."
Lewis, unfortunately, knows all about head trauma -- the former Baltimore Ravens running back sustained several concussions in his career ... including one in 2009 that he says was a horrifying experience.
The ex-tailback says he was knocked out during a game, and didn't feel quite right following the hit for months. At one point while trying to recover, he says he "woke up not really recognizing myself."
The 43-year-old -- one of only eight people to ever rush for more than 2,000 yards in an NFL season -- is now telling Tagovailoa to use him as a cautionary tale ... and truly take care of his head before returning to the field.
"You gotta be more smart and understand that you might have a family," Lewis said, "that you have other people that are more important than this game."