Kiwis' Southee doubtful for second Test against Sri Lanka

New Zealand pacer Tim Southee has sustained an ankle injury and is doubtful for the second Test match against Sri Lanka in the Basin Reserve.

He, however, will undergo a fitness test before the match starts Saturday.

Southee, who claimed six wickets in the eight-wicket win over the tourists in Christchurch, has what skipper Brendon McCullum described as a "slight ankle issue".

"We'll see how he pulls up in the morning," McCullum told AAP.

The Black Caps would not risk Southee who will also be one of their spearhead in the upcoming World Cup, and thus may bring in Doug Bracewell who has already played 18 Tests for his country.

"If we think that he's a risk that is not worth taking, then we won't take it, but if he thinks he's OK and we don't think there's a major risk there, then Tim will start," the skipper said.

"Doug Bracewell's bowling the house down as well and if he does get an opportunity, I'm very confident that he'll perform too," McCullum added.

Southee has so far picked up 134 wickets from 38 Tests.