'He's been getting knocked about': Leeds Rhinos coach Rohan Smith reveals why Corey Johnson got the nod over Jack Sinfield for Castleford Tigers derby

Sinfield was in Rhinos’ initial squad, but took 18th man duties while Johnson, normally a hooker, partnered Aidan Sezer in the halves.

Smith was forced to make a change when Blake Austin was ruled out because of a calf muscle injury.

Sinfield, 17, is a specialist stand-off/scrum-half and made three appearances during an injury crisis earlier in the season, including his debut against Castleford Tigers at the Jungle on Easter Monday.

Johnson, 21, played twice at the start of the year but had a spell on the sidelines with a knee injury before making his comeback in the reserves and on dual-registration with Bradford Bulls.

Last Saturday’s game was his fifth senior appearance for Rhinos and Smith said: “Corey has been playing there [stand-off] a little bit at Bradford in the Championship, which is obviously tough, hard, physical games.

“He is a bit older, a bit more mature than Jack.

“Jack has done a good job and he is training well.

“Jack has also been getting hit very hard, often, after he passes the ball in other grades he has been playing in.

“He has been getting knocked about a bit, he is a 17-year-old kid and I am conscious of taking care of him there a little bit.”

Smith stressed: “He’s fine, it’s not him - he’s as tough as any 17-year-old kid, but I thought it was a good opportunity to get Corey in.

“He hasn’t played much in Super League and I believe he is a long-term Super League player.”

Meanwhile, Sinfield is one of six Rhinos players selected for this season’s final Academy Origin encounter, at Wakefield Trinity’s Be Well Support Stadium, Belle Vue, on Sunday, July 24.

He has been drafted into the Lancashire squad.

Rhinos’ Bailey Aldridge and Max Simpson have been called up to join clubmates Alfie Edgell, Jake Higgins and Riley Lumb in the Yorkshire group, who trail 2-0 in the series.

Wakefield’s Oliver Pratt is also in the Yorkshire 21.