Shaquille O'Neal sparks concern by tweeting photo of himself in a ...

Shaquille O'Neal has posted a photograph of himself in a hospital bed, sparking concern among fans for the 'NBA on TNT' co-host.

Dailymail.com can confirm the 51-year-old underwent hip replacement surgery. 

O'Neal posted the picture of himself on Twitter along with the caption: 'I'm always watching @TurnerSportsEJ and @Candace_Parker miss y'all.'

The Twitter handles belong to his TNT co-hosts, Ernie Johnson and Candace Parker. Parker responded online, writing: 'Love ya big Fella.'

Former NBA stars Steve Smith and Roy Hibbert both shared their concern for O'Neal on Twitter. 

Shaquille O'Neal has posted a photograph of himself in a hospital bed, sparking concern among fans for the 'NBA on TNT' co-host

'U good big man?' asked Hibbert. 

'Get Well Big Fella,' Smith added.   

The 7-foot-1 O'Neal isn't known to be battling any health issues, and remained healthy for most of his 19-year NBA career. 

His mentor and father figure, Philip Arthur Harrison, died of a heart attack in 2013, but the US Army Sargent was O'Neal's stepfather, and not related to him by blood.

O'Neal was out sick earlier in March, although it remains unclear why he was absent. 

‘We called the hospital every day checking on you,’ joked co-host Charles Barkley on TNT’s studio show. 

O'Neal was out sick earlier in March, although it remains unclear why he was absent