Alex McLeish axed Birmingham striker Cameron Jerome from Saturday's starting line-up against Stoke for fear of burn-out.
The 24-year-old has been a virtual ever-present this season and has worked tirelessly up front, often as the lone forward. McLeish felt Jerome had lost his edge - and confidence after a recent goal drought - but he responded by coming off the bench to create the late winner for Nikola Zigic against Tony Pulis's side.
McLeish said: "I spoke to Cameron before the game. I try to communicate with players who have maybe been left out from the week before. I explained to Cameron I want to keep strikers with an edge because Cameron has run for fun from the start of the season right up to now."
He added: "You end up burning a guy out big time, especially a guy who has pace and power.
"I thought 'it will do you no harm, have a wee look at things off the bench, come on and make an impact'.
"I said 'it can change with a click of your fingers and your confidence can soar overnight'.
"I'm sure, with the performance when he came on, that will be the case with Cameron."
McLeish is confident on-loan striker Obafemi Martins will make an impact for Blues once he has settled in.
The former Scotland boss said: "Oba has got to adapt and we will be working in training on him working with our strikers. I felt they were a bit far apart at times against Stoke.
"But you saw on Saturday some of the strength he has got. That is the type of impact we are looking for Martins to make."