Everton winger Steven Pienaar is to miss the start of the new Premier League season due to a hamstring injury.

The South African, who played a part in his side's pre-season friendlies against Swindon Town and Stoke City earlier this month, picked up the injury in training and was forced to miss out on his side's 3-1 win against Hearts on Sunday.

"Obviously it was a really sad moment for all of us when Stevie picked up that injury in training," manager Roberto Martinez told the Everton website. "He's gone back now to be fully assessed by our medical team at Finch Farm and we'll get the results very soon.

"But it does seem it's a problem with his hamstring and clearly he's going to miss the start of the season, which is a real shame because Stevie worked with fantastic results and fantastic signs over the first three weeks or pre-season."

Pienaar also suffered disappointment last season as injury limited him to just 11 appearances for the Toffees.