The 22-year-old has scored nine goals so far this season and played a part in many more, and the new manager knows Boro cannot continue to rely upon him one man so heavily.
"If you look at the statistics, you will realise how important he's been to the club this season," said Strachan. "The rest of us have to be able to say, 'You can have an off-day and not be at your best'. We have to be a more rounded team."
Johnson missed a game-saving penalty in last Saturday's 1-0 home defeat by Plymouth, but his manager is not dwelling on that.
He said: "I think he's entitled to do something wrong every now and again. His record is phenomenal this season, but we have to be a whole team and not rely on one or two players."