Newcastle's coaching staff are concerned the club are missing the presence of midfielder Mohamed Diame, according to a local report.
The central midfielder's time with the Magpies came to an end because of the club's policy not to offer players over the age of 30 new long-term contracts.
It's alleged by ChronicleLive that some members of the coaching team are worried that Newcastle lack energy and power in midfield, attributes that Diame offered to the team despite not always being in favour with former manager Rafa Benitez.
Diame has subsequently signed for Qatari giants Al-Ahli, and the Magpies have experienced an inconsistent start to the 2019/20 campaign in his absence.
An impressive 1-0 win away at Tottenham has been overshadowed by a number of underwhelming results since, including a 3-1 defeat to Liverpool and a 1-1 draw with basement club Watford.
But their latest encounter - a lacklustre 0-0 draw with Brighton & Hove Albion at St James's Park - went some way to highlight some of the problems Bruce has inherited Tyneside.
Jonjo Shelvey was erratic in possession before being hauled off midway through the second half - with replacement Ki Sung-yeung not faring much better. Isaac Hayden is the Magpies other starting midfielder, but he too has suffered with fluctuation in form since re-establishing himself the side.
Brighton's domination of possession and creation of chances of will was of real concern to home supporters, with Diame's combative style missed in a lacklustre display from the Magpies.
They face Leicester City, Manchester United and Chelsea in their next three Premier League fixtures, and Bruce will know that his players need to up the ante - and evoke Diame's never-say-die attitude - if they want to pick up points.