The Magpies captain was an unused substitute against the Hammers with Emil Krafth handed a surprise start instead.
Lascelles watched on as his teammates shipped three second-half goals having led 2-1 at half-time.
Bruce missed the presence of his captain in the backline but felt he had no choice but to leave him out due to his fitness levels.
Lascelles missed the remaining eight games of last season after undergoing surgery on his foot.
"Jamaal has had a difficult pre-season," Bruce said. “He’s just getting over an operation and obviously he needs minutes.
“It’s been a toil for him, which is understandable. I just thought, physically wise, that was the best bet.
“With another week, or ten days or so of training, hopefully we’ll see the return of the captain.”
We’ve gathered the best of today’s Premier League speculation below…
5. Nandez price drops
Cagliari are willing to drop their price tag for Leeds United target Nahitan Nandez to around £22.1 million. (Calcio Mercato) (Photo by Miguel Schincariol/Getty Images) Photo: Miguel Schincariol
6. Cunha wants top move
Leeds United linked Matheus Cunha has rejected a lucrative offer from Zenit St. Petersburg and only willing to leave Hertha Berlin this summer to join a "top club". (Bild) (Photo by Alexander Hassenstein/Getty Images) Photo: Alexander Hassenstein
7. Leeds tipped to move for Winks
Leeds should do everything in their power to bring Harry Winks to Elland Road as their search for midfield reinforcements continues, according to Paul Robinson. (Gambling.com) (Photo by Catherine Ivill/Getty Images) Photo: Catherine Ivill
8. Toon among Kamara suitors
Newcastle United, West Ham, Arsenal, and Watford are among the clubs who have enquired about Rangers midfielder Glen Kamara. (90min) (Photo by Steve Welsh/Getty Images,) Photo: Steve Welsh