The June quarter is usually considered as a seasonally strong period for the IT sector.
Even though the company's revenue figures are not public, it has so far raised $93 million in four rounds of funding.
Pratt, who joined the firm in 2004, has left the company to start his own entrepreneurial venture.
Most high-profile exit since co-founder Narayana Murthy returned to the helm.
In the seventh top level exit in six months at Infosys, Subrahmanyam Goparaju, Senior Vice President and a member of the Executive Council that frames business strategy, has resigned.
Given their growth prospects and reasonable valuations, Mindtree, Hexaware and NIIT remain top picks of most analysts.