Ben Stokes is playing for Durham against Northamptonshire, his third County Championship match of the season. Durham chief executive Tim Bostock says he is "bemused" about doubts around England Test captain Ben Stokes' "state of mind" following an incident in a London nightclub.

All-rounder Stokes, 35, was left out of England's squad for the second Test against New Zealand after breaking the team's midnight curfew. Speaking at a sombre press conference on Monday, England coach Brendon McCullum repeatedly said he was "worried" about Stokes while refusing to back him to return as skipper.

Bostock said Stokes, who is playing for Durham against Northamptonshire on Friday, is "absolutely fine". "It is just normal Ben," Bostock told BBC Look North. "I was a little bit bemused by some of the comments about his state of mind and maybe in the first 24 hours when this exploded, I am sure he was thinking, 'What has happened here?'. "He has been absolutely fine. He is very positive and is always very positive."

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An investigation into the nightclub incident, when Stokes and pace bowler Gus Atkinson were present when a member of security staff was struck by a Saracens rugby player, remains ongoing. While the England and Wales Cricket Board is hopeful of a swift resolution, no update is expected on Friday. There remains a growing likelihood Stokes will return as England captain for the third Test at Trent Bridge next week.

"This is a difficult situation," added Bostock. "It sounds like common sense is prevailing. "We are happy to have Ben here but not under these circumstances."

England introduced a curfew after a number of off-field incidents dogged their defeat in last winter's Ashes in Australia. In the aftermath of the incident on 8 June there were fears Stokes would retire, ending a storied England career. Those fears were allayed when he returned to training with Durham last weekend. He has continued to train with his county through the past week and, with the investigation not preventing the all-rounder - nor fast bowler Atkinson - from playing in domestic, both returned to the field on Friday.

Bostock's words were reflected in comments by others around Durham. Stokes had been "just like Stokesy" in recent days, one source told BBC Sport. Durham has been his county home throughout his career. He has regained fitness from previous injuries by running around the athletics track behind the Finchale End, and by completing shuttle runs on the outfield.

In the warm-ups before day one against Northamptonshire, he was throwing balls to former Durham captain Scott Borthwick, who was best man at Stokes' wedding. The media interest in Stokes was clear. Various TV camera crews and photographers were pointing their lenses towards the all-rounder before play.

On the field, all seemed familiar. Stokes bowled better than his figures - 0-53 across his first three spells - suggest. He had a catch dropped in his first over by Ben McKinney standing at leg slip and any idea Stokes may have lost a spark since the nightclub incident was not in evidence here. At the end of his sixth over, his backside almost touched the pitch as he squatted in appealing for lbw. When former umpire James Tredwell - the former off-spinner who played 20 times with Stokes for England - turned down the decision he slapped the pitch in frustration.

In the field, Stokes was often stood with his arms folded at mid-off under his blue cap - as he so often has been for England. He also appeared to give occasional tactical advice to Durham team-mates - spinner Callum Parkinson, in particular.

In Cardiff, meanwhile, Atkinson had figures of 2-33 when bad light stopped play in the evening session. If Stokes and Atkinson are picked to play in Nottingham they may have to be withdrawn from the latter part of the county fixtures, given the Test begins on Thursday.

Spectre of Stokes hangs over England at The Oval. 'Travesty' if Stokes doesn't captain England again - Vaughan. Stokes in good spirits - Durham boss Campbell.