LONDON (Reuters) - Sainsbury's (>> J Sainsbury plc), Britain's No. 2 supermarket chain, on Friday named Simon Roberts as its new retail and operations director but may have to wait until July 2017 before he can start.

Roberts was most recently executive vice president of Walgreens Boots Alliance (>> Walgreens Boots Alliance Inc) and president of Boots in the UK & Ireland.

Prior to that he was managing director of Boots UK and is also a former executive of Marks & Spencer (>> Marks and Spencer Group Plc).

He is currently on gardening leave as per his Walgreens contract.

Sainsbury's has been without a permanent retail and operations director since Roger Burnley quit the firm in October 2015 to join Asda (>> Wal-Mart Stores, Inc.).

Before Roberts joins, Sainsbury's director of non food operations Jon Hartland will continue to fill the retail and operations director brief as well.

On Wednesday Sainsbury's reported another drop in quarterly underlying sales and cautioned that it did not expect a change to competitive market conditions any time soon.

(Reporting by James Davey, Editing by Paul Sandle)