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.
"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."
Source: PA
Source: PA