The Celtic defender has been one of a host of triallists aiming to impress Appleton in an effort to win a contract. The Blues boss is looking at trying to keep him with the club to run a closer eye over him in the coming days. The 21-year-old has caught the eye with a couple of sound displays in pre-season outings so far. Thompson came off the bench at Aldershot last week and got 25 minutes under his belt. He then followed that with a composed 76-minute display in the 3-0 success against Bolton on Saturday. The 6ft 4in centre-back has been told he has no future at Parkhead by Bhoys boss Neil Lennon. Scottish Premier League outfit Aberdeen are also keen on Thompson who has had loan spells at Rochdale, Peterborough and Chesterfield. Appleton is aware of Thompson from a period he had on trial at West Brom when the Pompey boss was at the Hawthorns. He is still waiting to get the green light to recruit the host of triallists bidding to earn a Pompey contract. Appleton would like to see Thompson remain beyond tomorrow’s trip to AFC Wimbledon. The Blues boss is looking to speak to Celtic to see if he can receive the green light to allow that to happen. Appleton said: ‘Thompson is at Celtic at the minute. They were happy for him to come down and train for a week or so with us. ‘We will have to speak to them and see if they are happy for him staying for another week. Then we will make a decision when we are in the business of being able to make a decision.’