"We may have to bring in one or two bodies because we had to rely on youngsters here," Adams said.
"I'd have preferred to have come here with a full squad, but regardless of that I didn't feel that we really got going and didn't really do enough going forward."
Adams added: "It was a fair result. They have some very good players and it was always going to be difficult coming here, but if you are going to lose a game at least we have had a go."
The result could and should have been settled far earlier, only breath-taking second-half saves by Vale goalkeeper Chris Neal denying shots from Trotta and Clayton Donaldson.
Before that Blackburn loan signing Alan Judge stung Neal's fingers with two dipping drives before Trotta gave the hosts the lead, turning on the edge of the box to rifle home into the bottom corner.
Donaldson thought he had sealed the points on the hour-mark when he got above Neal to head home, but the effort was ruled out to the anger of the Griffin Park crowd.
Brentford made sure of maximum points late on as the Londoners broke quickly and Jake Bidwell's left-wing cross found Grigg unmarked in the middle to drill home from 12 yards.
Bees goalkeeper David Button was not called into action, a glancing Tom Pope header early on the visitors' only real glimpse of goal.