When Apple unveiled its new smartphone last week, it also announced some changes to its iPhone lineup. For starters, the 16GB iPhone 4S is going to drop to just $99 with a two year contract.

In addition, the company is also getting rid of the 3GS, making the iPhone 4 its $0 offering. But according to some new information, it doesn’t look like all providers are going to carry it…

9to5Mac reported earlier this evening that Sprint is going to be removing the iPhone 4 from its lineup starting September 21st, the same day that the above-mentioned pricing is to go into effect.

We can now confirm the information, as iDB has gotten its hands on Sprint’s internal iPhone 5 Launch Guide. In it, the carrier tells its employees that the iPhone 4 will be removed from its Planogram, or pricing catalogue, this week with “more information and instructions” to follow soon.

There’s a good chance that Sprint is removing the handset because it can’t afford to eat the $500+ subsidy on each one. Remember, Sprint is the last of the big three carriers offering unlimited data.

Apple did say that the free iPhone 4 would only be available on select carriers. So it’ll be interesting to see how this all shakes down over the next few weeks, at Sprint and at other wireless providers.