Source - TV NZ 

He has recently featured for the Northern Knights as a batsman only.

Black Caps coach Mike Hesson said that would remain Anderson's only role at this stage.

The T20 squad play two matches against Sri Lanka, with the first on January 7 at Mount Maunganui before heading to Auckland for the Eden Park match on January 10.

"It's been a long process for Corey," said Hesson.

"But we've been happy with his recent progress and the fact he's managed to string a few games together for the Knights," said Hesson.

"We’ve got a plan in place for when we hope to have Corey back bowling. He’s getting closer, but we’ll be taking a precautionary approach.We’ve seen how dynamic a batsmen he is and can threaten any bowling attack in the world. It’ll be great to have him back in the mix."

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We're also looking forward to having Grant back with us after recovering from the from his arm injury. He brings a lot to the squad and obviously has experience in pressure moments, which is key to batting in the middle order in Twenty20.

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- Hesson said

With the ICC World Twenty20 in India in March, Hesson said these matches would provide key preparation.

"These will be our first Twenty20s of the summer and with the World Cup just around the corner these are two of the five games that the players can use to push their case for selection, but also more importantly win games for New Zealand.

"It’s a side with a good balance of talent and experience."

Nathan McCullum was not available for selection due to a knee injury. He’s on track to return to the Ford Trophy mid-January.

Black Caps Twenty20 Squad v Sri Lanka
Kane Williamson (c), Corey Anderson, Trent Boult, Grant Elliott, Martin Guptill, Mitchell McClenaghan, Adam Milne, Colin Munro, Luke Ronchi, Mitchell Santner, Ish Sodhi,Tim Southee, Ross Taylor.

Black Caps Squad for final two ODIs against Sri Lanka
Brendon McCullum (c), Trent Boult (will return for fifth ODI), Doug Bracewell, Martin Guptill, Tom Latham, Mitchell McClenaghan, Adam Milne, Henry Nicholls, Luke Ronchi, Mitchell Santner, Ish Sodhi, Tim Southee, Ross Taylor, Kane Williamson.