Leeds United expect defender Sam Sodje to be fit for Thursday's play-off semi-final second leg at home to Millwall.
The Reading loanee dislocated his shoulder in the second half of Saturday's 1-0 first-leg defeat, but popped it back in and played on.
"He's a hard lad and carried on, but you need that toughness in the play-offs, "Grayson told BBC Radio Leeds.
"I'm sure he will be fine for the second leg and be back putting his body on the line and making the tackles."
Meanwhile the Football Association have started to investigate the pitch invasion by Millwall fans that marred the encounter at the New Den.
Leeds goalkeeper Casper Ankergren claims to have been assaulted during the incident, but Grayson has played it down.
"Play-off semi-finals always generate a hostile atmosphere and people get excited," he said.
"I thought the authorities handled it well and our players didn't responded to anything.
"My job is to protect my players, they are all OK and we haven't made too much of it.
"I certainly wouldn't take on Casper."
BBC Radio Leeds has full match commentary of the second leg on 92.4 FM, 103.9 FM & DAB. All the build-up starts at 1900 BST on Thursday live from Elland Road.
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