Matt Prior will miss the start of Sussex's NatWest T20 Blast campaign after beginning a new treatment programme in an attempt to cure an Achilles injury.

Prior has been provisionally pencilled in to make his comeback as a specialist batsman in the County Championship match against Middlesex on May 26.

If he comes through that test unscathed he will then keep wicket for the first time since December in the four-day game against Nottinghamshire at Hove at the start of June to prove his fitness ahead of the first Test of the summer against Sri Lanka.

It means the 32-year-old will not only miss Sunday's Championship clash with Durham at Hove but their opening three T20 games as well as the T20 friendly with Sri Lanka on May 18.

Prior played in the opening Championship game of the summer against Middlesex as a specialist batsman - scoring 125 - but has missed the subsequent three matches as England carefully manage his rehabilitation.

Coach Mark Robinson said: “Matt's injury is not responding the way the medical team had hoped so they are trying a new programme. Instead of putting a time on it and trying to get him ready for the next game they are giving him a block of time to try to get it right.

“He's got something like a 20-day window now to do have the treatment he needs and to work in the pool and the gym to make it stronger. We're using the facilities at Brighton University and Brighton football club so hopefully the new tactics will pay dividends.”

Although Prior will miss the Durham game Sussex will welcome back skipper Ed Joyce and Matt Machan from international duty on Sunday and expect Chris Jordan to also be made available by England.