Tom Curran and Jamie Overton in performance squad
Both players feature in the England Lions programme earlier in the year although Overton was forced home due to a foot injury.
Curran, who was born in Cape Town, enjoyed an impressive 2015 season with Surrey where he claimed 76 Championship wickets and he became eligible for England at the end of last year.
Overall, the performance squad includes the 22 players who are centrally and incrementally contracted by the ECB plus eight without current deals. Alongside Curran and Overton, this includes Zafar Ansari, who was named in England's Test squad for the series against Pakistan before breaking his thumb the same day, Sam Billings, Liam Dawson and Reece Topley who were all part of the World T20 squad, the left-arm quick Mark Footitt who toured South Africa plus Jake Ball who has earned his maiden Test call-up.
Andrew Strauss, the director of England cricket, said: "This is the first time in two seasons we have selected an England Performance Squad. I feel that it is important that we do so to enable our staff to monitor effectively those players who are on our radar, but not necessarily part of one of the England teams. It is also important to point out that it does not confine the selectors to pick from this squad."
Performance squad Moeen Ali*, James Anderson*, Zafar Ansari, Jonny Bairstow^, Jake Ball, Gary Ballance^, Ian Bell*, Sam Billings, Stuart Broad*, Jos Buttler*, Nick Compton^, Alastair Cook*, Tom Curran, Liam Dawson, Steven Finn*, Mark Footitt, Alex Hales^, Chris Jordan^, Eoin Morgan*, Jamie Overton, Liam Plunkett^, Adil Rashid^, Joe Root*, Jason Roy^, Ben Stokes*, Reece Topley, James Vince, David Willey, Chris Woakes, Mark Wood*