Models of Research in Motion's PlayBook tablet have been pulled from online stores of some top retailers in the U.S. and Canada, a move one analyst said could be a sign that the company is readying a successor tablet.

The PlayBook tablet is no longer listed on the online stores of consumer electronics retailers including Wal-Mart, Best Buy, RadioShack and Staples. The products are listed as being out of stock in Office Depot's online store.

In the BlackBerry maker's home country of Canada, only the 32GB model is available on the websites of retailers Futureshop and Best Buy Canada, at a discounted rate of C$149.99 ($153). The 16GB and 64GB PlayBook models are out of stock.

However, the tablets remain available on RIM's own online store.

RIM did not respond to requests for comment.

The first PlayBook shipped in April 19, starting at $500 for a 16GB model, but has sold poorly since. PlayBook sales dropped to about 130,000 in RIM's most recent fiscal quarter, which ended on Sept. 1.

The company's stock of PlayBooks may have run out, and the company may be getting ready to launch a new version of the tablet, said Bob O'Donnell, program vice president for clients and displays at IDC.

RIM has said nothing recently about a new PlayBook, but if one were to come, it could be running the upcoming BlackBerry 10 operating system, O'Donnell said. RIM is aggressively pushing the new OS, which will be on new BlackBerry smartphones later this year.

"There have been rumblings of RIM doing a second-generation [PlayBook] product," O'Donnell said. "I don't think they are going to quit the market yet."

RIM said in August it would refresh the PlayBook lineup with a 4G LTE model that would be initially available through Canadian carriers and in other countries at a later date. The PlayBook LTE model is already available through Canadian carriers, and is listed on RIM's as "coming soon" to the U.S. However, the model is not available through retail stores.

In early October RIM pushed out an update to the BlackBerry PlayBook OS, version 2.1, for the LTE and existing Wi-Fi only versions of the tablet. The update includes features such as the ability to compose SMS messages when connected to a BlackBerry smartphone over Bluetooth. There is also improved support and compatibility for Android apps.

Agam Shah covers PCs, tablets, servers, chips and semiconductors for IDG News Service. Follow Agam on Twitter at @agamsh. Agam's e-mail address is agam_shah@idg.com