The Gunners' London rivals both play Premier League fixtures on Sunday afternoon having featured in the last eight of Europe's second cup competition on Thursday evening.
And, with Arsenal poised to capitalise on any mistakes in the chase for Champions League football, Bould believes the energy expended in Europe could be crucial.
"Being in Europe can be a factor," he told reporters.
"It's extremely tough, the travel. It can affect and I think sometimes, if a negative result comes along within that time span, it can affect your season. It's going to be tough."
The 50-year-old also backed his side to keep up their improving form during the run-in, starting with Saturday's clash against West Bromwich Albion at The Hawthorns.
"All along, we've known it's how we do over the next few months," he added.
"We're capable and we've got a good run going. We just need to win games and put pressure on and hope that one of them [the teams above us] will wilt. We're aiming for as high as we can get.
"West Brom is a really tough game and Steve Clarke has done a magnificent job there. They've had a little dip but they've been more or less up there for the whole season.
"They've got a good back four, a good goalkeeper and they don't let in an awful amount of goals. We're under no illusions. We know it's going to be tough but we're more than capable."
