Mark Warburton says on-loan Fulham frontman Marcello Trotta was rested for Brenford's 3-1 win against Notts County.
The Italian U21 international watched from the bench as Adam Forshaw's penalty and Alan Judge's brace saw the Bees tighten their grip on second spot.
Clayton Donaldson was preferred in the central striking role, while Will Grigg appeared as a second-half substitute.
Warburton said: "We've got a lot of games coming up. We forget how young these players are.
"Trotta's only 21, so we need to rest them and look after them. It's a squad game, and you don't win anything with 11 players."
James Tarkowski was substituted after the break as he is just a booking away from a two-game ban.
However, his replacement, Harlee Dean, was yellow-carded and is also walking a tightrope for the next couple of matches.
Warburton added: "Harlee's booking was bemusing. He was on eight yellow cards but came on and did a good job for us.
"He didn't lunge into a tackle, so it was frustrating for him and for us if a player gets a needless caution. I didn't think there was much wrong."
