The mystery man in the background and other things spotted in Middlesbrough training video

Middlesbrough's pre-season preparations have continued at Rockliffe this week as they get ready for Friday night's trip to York City's LNER Community Stadium. The friendly is their second of the summer after last weekend's victory over Bishop Auckland.

The game against the National League side will be the final game before Chris Wilder's side head off to Portugal for a week-long training camp in the Algarve. With Boro flying on Saturday after the game at York, Thursday's training session at Rockliffe is likely to have been their last there for over a week.

Naturally, at this time of year people pay close attention to training videos to see if there is anything interesting to be spotted or learned from them. Boro put out a five-minute video and pictures of the session on Thursday as they prepare for their next friendly. Here's what we spotted in the video.

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Eagle-eyed Boro fans were quick to spot a mystery man running in the background with sports scientist Frankie Hunter when the training session moved into a practice game. There was naturally talk about who it was and whether it was perhaps a new trialist or even a new signing.

The truth is a little less exciting. The mystery man isn't a new signing but instead Caolan Boyd-Munce. The Northern Ireland international can be spotted earlier in the session taking part in the running drills but wasn't involved in the contact game as he nurses an injury. He missed the trip to Bishop Auckland last weekend because of it and, while not a serious injury, it was enough to stop him from taking part in contact training.

Martin Payero could not be seen in training as he remains out with