Wilson said the decision to sack assistant manager Micky Mellon and goalkeeper coach Willcock was made because the 'synergy' was not right among the coaching staff.
The decision was made by Wilson and supported by the board. The club is looking to fill both positions, with Wilson's former assistant at Sheffield United the favourite for the assistant role, but appointments are unlikely before tomorrow’s match at home to Bournemouth. The goalkeepers are currently training themselves and ex-Red Paul Heckingbottom will assist Wilson on the touchline.
The manager said: "It was one of the toughest decisions I have ever had to make but I felt it was right. It came from me and the club supported me. Mick and Ian are both absolutely cracking lads and they will definitely get back into football, hopefully sooner rather than later.
"It's never easy when someone has to leave a club and I should know because it has happened to me. They haven't done anything wrong. It's about synergy. It was important that I felt right. Managers often work with the same coaching staff for a reason and that was one of the main factors.
"It was done very professionally. The two lads were disappointed but they understood it. We have to move on. There was never going to be a right time to do it. If we hadn't done it now, people might have asked us why we didn't at the end of the season."
Former Fleetwood Town manager Mellon was brought in as assistant manager by close friend David Flitcroft as well as coach Martin Scott in December 2012 and helped the Reds stay up in remarkable fashion last season. The club refused to allow Conference outfit Forest Green to speak to him early in this campaign and he was the Reds' caretaker manager for three games after Flitcroft and Scott left in November before being made assistant to Wilson.
Willcock joined from Rochdale along with Keith Hill and Flitcroft in 2011. The only member of that group who remains with Barnsley is fitness coach Jon Lucas.