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…
1. Clarets lead Maitland-Niles race
Burnley have emerged as favourites to land Arsenal midfielder Ainsley Maitland-Niles this summer. (SkyBet) (Photo by GLYN KIRK/AFP via Getty Images) Photo: GLYN KIRK
2. Nice keen on Edouard
French club Nice are lining up a bid to sign Brighton target Odsonne Edouard from Celtic this summer. (Football Insider) (Photo by Steve Welsh/Getty Images) Photo: Steve Welsh
3. Manchester United want midfielder
Manchester United would prefer to sign a midfielder over a right-back before the transfer window slams shut on August 31st. (ESPN) (Photo by Henry Browne/Getty Images) Photo: Henry Browne
4. Villa face Chukwuemeka competition
Aston Villa have signed Northampton Town youngster Caleb Chukwuemeka, beating Rangers to his signature. (Official announcement) (Photo by Pete Norton/Getty Images) Photo: Pete Norton