But he has recovered to take a place on the bench as Danny Wilson makes five changes to the starting line-up at BT Sport Cardiff Arms Park.
Gareth Anscombe reclaims the number 10 jersey in an otherwise unchanged backline. Up front, Nick Williams is back at number eight and Gethin Jenkins, Kristian Dacey and Taufa'ao Filise form the front-row.
Wales' Capital Region have not triumphed over the Dublin-based province since 2011 but go into the encounter on the back of their best start to a season ever.
Victories over Edinburgh, Munster, Glasgow Warriors and Zebre have seen Danny Wilson's men climb to second in the PRO12 table but he is well aware of the magnitude of Saturday's task.
Wilson: "Leinster were very good (against the Ospreys) and very clinical. They showed their strengths up front and their defensive game forced a fair few turnovers and penalties.
"So they are a tough team to play, whether home or away, but we have to take some confidence from Glasgow and Edinburgh at home which were good wins, and Munster, who you can also put in that bracket as a top end side.
"They are a side we lost to last season so we definitely want to put that right but we're under no illusions that we are playing a fully loaded Leinster. It would be a huge scalp to take.
"But confidence is good, confidence is high off the back of winning four games and we go in knowing it's a home game and will hopefully perform as we know we can."
Jenkins, who has signed a contract extension, will resume the captaincy for the top four clash.
Tickets for Cardiff Blues v Leinster in the Guinness PRO12 are still on sale and can be purchased today by clicking here or calling the ticket office on 029 20 302030
Cardiff Blues: Matthew Morgan; Blaine Scully, Cory Allen, Rey Lee-Lo, Tom James; Gareth Anscombe, Lloyd Williams; Gethin Jenkins (capt), Kristian Dacey, Taufa'ao Filise, George Earle, Josh Turnbull, Sam Warburton, Ellis Jenkins, Nick Williams.
Replacements: Matthew Rees, Rhys Gill, Scott Andrews, Macauley Cook, Josh Navidi, Tomos Williams, Steve Shingler, Dan Fish
Guinness PRO12 Blues News
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