The club are no closer to a diagnosis and his expected return date continues to be pushed back.
The 28-year-old had been pursued by West Bromwich Albion during the summer transfer window after having a successful loan spell with the Baggies last season, scoring 24 goals.
Ahead of their match against Watford on Saturday, quotes carried by the Newcastle Chronicle, the Newcastle boss said: “Injuries are frustrating for any manager.
“Gayle is a concern as he isn’t getting any better, he is going to see another specialist.”
The Magpies injury problems continue after Matt Richie was confirmed to have suffered ligament damage during their second round exit from the Carabao Cup at the hands of Leicester on Wednesday, and is expected to be sidelined for around two months.
On Ritchie, Bruce said:
This latest injury takes Newcastle’s tally of first team players struggling with knocks up to 11.
Bruce remains without Florian Lejeune and Andy Carroll for Watford’s visit to St. James’ Park but the 58-year-old did allude to Carroll's potential return date:
Newcastle face the league’s bottom side as they look to build on their 1-0 win over Spurs. A second consecutive victory would further help to ease the pressure on the manager which has mounted ever since he replaced fan favourite Rafa Benitez earlier in the summer.
Source : 90min