* Head of Americas and manufacturing Ashok Vemuri resigns
* Company names Sanjay Jalona global head servicing manufacturing clients (Adds investor comment, background)
By Harichandan Arakali
BANGALORE, Aug 28 (Reuters) - Infosys Ltd's Americas head and global manufacturing chief, Ashok Vemuri, has resigned in the most high-profile exit since co-founder Narayana Murthy returned to the company to reverse two years of floundering growth.
Vemuri, a board member, was widely considered a contender to succeed chief executive S.D. Shibulal, another of the company's seven co-founders, when his term ends in mid-2015.
A series of top-level departures has followed Murthy's surprise return on June 1 as executive chairman, including global head of sales and marketing Basab Pradhan and Sudhir Chaturvedi, head of financial services in the Americas.
Murthy has said he will take tough decisions to restore the company's fortunes over the next three years and refocus it on winning large outsourcing contracts.
A strategy to raise revenue from software products and consulting, at the expense of large outsourcing contracts, contributed to a series of disappointing results over the last two years.
A transition plan to replace Vemuri is in place, Infosys, India's No. 2 software services exporter, said in a statement.
"It's certainly not very good news...this is certainly a big event," said Phani Sekhar, a fund manager with Mumbai brokerage Angel Broking, who holds Infosys stock.
"You don't know what kind of sales reorganisation the company is planning and whether they will be able to get the right kind of people in place...so there is a certain amount of uncertainty now," Sekhar said.
Narayana Murthy brought in his son Rohan Murty, a Harvard graduate, as executive assistant, a move seen at odds with the company practice of not involving the children of the founders in senior management.
Vemuri's exit "could also be because of some of the moves he (Narayana Murthy) is planning, we'll have to wait and see," Sekhar said.
Sanjay Jalona, currently regional head for manufacturing in North America, will take over as global head of manufacturing, Infosys said. (Editing by Aradhana Aravindan and David Cowell)