Translation ... stop messing around and get a long-term deal done already.

Bell has been beefing with the Steelers for years -- demanding (and failing to get) a long-term contract. Instead, the team hit him with the franchise tag for the past 2 seasons.

Bell has threatened to hold out and even retire if the two sides don't get a long-term deal done -- and Bettis says it's in the best interest of BOTH sides to make something work.

"Le'Veon, you're not going to be as good going somewhere else because they're not going to have the offensive line, they're not going to have the quarterback, the receivers that they have in Pittsburgh."

"You have a full complement around you that allows you to be as great as you want to be."

As for the Steelers, Bettis says there's little risk in signing Bell to a long-term deal because he'll be able to produce at a high level for at least 5 more years.

By the way ... Bettis is competing in a golf tournament next week that features a Korbel champagne celebrity cork-shooting contest -- and you gotta hear why he thinks Steph Curry shouldn't be the favorite!!