Celtic's transfer business is expected to be busy in the closing weeks of the summer window, according to journalist Roger Hannah. The Scottish Sun journalist predicts three potential exits from the club, including Alistair Johnston and Arne Engels. With the competitive campaign now just days away, Martin O'Neill has so far welcomed only two new arrivals, leaving sections of the support frustrated after anticipating a far more extensive rebuild. Despite those concerns, Hannah remains convinced that significant changes are still to come, suggesting both arrivals and departures will gather pace before the deadline. In an interview on Clyde Superscoreboard, Hannah said: "For me, there's parallels between this summer and the Ange pre-season. He came in, there was a bit of scepticism pre-season... I remember West Ham coming to Celtic Park and winning 6-2, and there was a lot of worry. There were a lot of deals done late on. There were outgoings - Ryan Christie went on to Bournemouth, Odsonne Edouard went on to Crystal Palace… there were guys that came in late on. I think there's going to be a lot of activity between now and the third of September at Celtic. I think there will be outgoings. It would not at all surprise me if Arne Engels, Reo Hatate and Alistair Johnston all follow Daizen Maeda out the door. It would not surprise me at all. And the key, then, is to make sure that Mika Baur comes in to replace Engels. Maybe Julian Araujo comes back to replace Alistair Johnston. They get somebody in to replace Reo Hatate in the middle of the park. I think there's a lot of work being done by Mark Cooper and that Celtic recruitment team. I think there will be a lot of activity in the last five weeks of the window."