BOSTON - Alphabet Inc, the new holding company for Google, has put Boston Dynamics, part of its robotics division, up for sale for lack of revenue potential.

The possible buyers include Amazon.com and Toyota Research Institute, Toyota Motor Corp's research and development company. Boston Dynamics, bought by Alphabet in 2013, is best known for building robots that look as if they belong in a science-fiction movie and are often co-developed or funded by the United States military.

But, executives at Alphabet, absorbed with making sure all the various companies under its corporate umbrella have plans to generate real revenue, concluded that Boston Dynamics is not likely to produce a marketable product in the next few years and have put the unit up for sale, people familiar with the company's plans said.

Google and Toyota declined to comment, and Amazon did not respond to requests for comment.

Google acquired Boston Dynamics in late 2013 as part of a spree of acquisitions in the field of robotics. The deals were spearheaded by Mr Andy Rubin, former chief of the Android division, and brought about 300 robotics engineers into Google. Mr Rubin left the company in October 2014. Over the following year, the robot initiative, dubbed Replicant, was plagued by leadership changes, failures to collaborate between firms and an unsuccessful effort to recruit a new leader.

At the heart of Replicant's trouble, said a person familiar with the group, was a reluctance by Boston Dynamics executives to work with Google's robot engineers in California and Tokyo, and the unit's failure to come up with products that could be released in the near term.

Boston Dynamic's products include Cheetah, which it claims to be world's fastest-legged robot and RiSE, a robot that climbs vertical terrains like trees and fences.

Tensions between Boston Dynamics and the rest of the Replicant group spilt into open view within Google, when minutes of a Nov 11 meeting and subsequent e-mail were inadvertently published to an online forum accessible to other Google workers.

Last December, Google announced that Replicant had been folded into Google's advanced research group, Google X. Boston Dynamics, though, was never folded into Google X and was instead put up for sale.

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