Strachan took over as Middlesbrough boss in October, when he replaced Gareth Southgate.
“I am nowhere near where I want. I am always searching to improve. I expect (chief executive) Keith Lamb to be very busy this summer,” Strachan told the Daily Mirror.
“I won’t put a figure on many players I want to bring in but it will be quite a few – and that’s not to worry players already here.
“It is simply that we have such a small squad.
“We will have to wheel and deal because these days, this isn’t a club that can just go out and take its pick on who it wants.
“Every manager is looking to complete his jigsaw puzzle but you cannot complete it if you have a few pieces missing.
“It’s my job to go out and get those pieces.”
