There are 2 definitive types of banana pups (aka suckers): Sword suckers, and water suckers.

Sword suckers are considered the "healthy" pups. they're the ones that grow upward like spears and take awhile to put out a true leaf.

Water suckers are the diminutive pups that show full fledged leaves early, but usually take a lot longer to grow.

Sword suckers are well-connected to the main corm, they grow as a true offshoot of the original banana plant, whereas Water suckers are often growing from a damaged or less-efficient section of the main corm.

As you've got yourself a chunk of corm with roots, there is a very decent chance you'll get a plant out of it. The only "problem" is it might be a weak growth, and the time it takes to grow and flower could be a LOT longer.

Basically, if you're willing to chance it, go for it! Just don't be surprised if you don't get a super healthy, overly happy plant out of it.

But as it continues to grow it will turn back into a healthy plant. Correct ?

Correct. If it survives its juvenile stage, you'll never know the difference down the line.