It must be a wrench to leave for players who have spent most of their careers at one club David Robertson was in tears as he waved goodbye to Tannadice on Sunday after helping Dundee United to a 2-1 win over Hearts. The midfielder is due to join St Johnstone in the summer and is looking forward to being part of Derek McInnes' squad at McDiarmid Park. He said: "Although it is very hard to leave Dundee United, I'm really looking forward to next season and I believe it is the right move for me. I needed a change of scenery and I think St Johnstone can do well next season. I have been at Dundee United for 10 years now, eight of which as a professional, so I'm looking forward to something new. It will be strange going into a new dressing room but I'm sure I can cope with it and hopefully I can do well from the start of the season." Robertson will be reunited with former team-mate McInnes and his assistant Tony Docherty when he moves to McDiarmid Park. He said: "Tony Docherty was my old youth team manager and he was outstanding. Derek was my first captain when he was at Dundee United and he was a total professional. I loved playing with him. I have only had good feedback from anyone who has ever spoken about the two of them so I can't wait to start working with them again." However, he said he will leave Dundee United with many happy memories, none more so than winning the Scottish Cup last season. He went on: "I have had an absolutely fantastic time at the club. I signed here when I was 14, probably around about the time that Eddie Thompson took over. I have been through a lot here. When I first joined we were fighting relegation but now I am leaving a club that has done very well. Obviously winning the Scottish Cup last season was absolutely fantastic. It is difficult to move on but I'm looking forward to the new challenge."