Penrith Panthers halfback Nathan Cleary is off for scans on his left knee on Saturday to determine how long he might have to spend on the sidelines.

The points-scoring machine did not return for the second half against the Canterbury-Bankstown Bulldogs at ANZ Stadium on Friday night, and in his absence his teammates almost pulled of a remarkable win.

When winger Josh Mansour crossed in the left corner and James Maloney converted from the sideline, the Panthers – who had been down 20-6 earlier in the game – came within two points, finally losing a close one 20-18.

But coach Anthony Griffin looked resigned to losing one of his chief playmakers for a game or two.

"We think he's got a medial ligament problem. It happened early in the first half, around the 11th minute," Griffin said.

"I didn't actually see it but the doctor tells me it happened early. They checked him on the field and he wasn't too bad. But when he came in and cooled down at halftime and they had another look at him, they pulled him.

"We'll get a scan tomorrow and see what's going on."

The initial diagnosis is a one to four-week injury, depending on how badly Cleary has strained the ligaments on the inside of his knee. 

Panthers halfback Nathan Cleary ices his injured knee.
Panthers halfback Nathan Cleary ices his injured knee. ©Grant Trouville/NRL Photos

For the second 40 minutes on Friday night, Maloney moved into No.7 and bench utility Tyrone Peachy came on at No.6.

It looks like Griffin will keep that combination as the Panthers have a short turnaround before their next assignment in Townsville on Thursday night against the North Queensland Cowboys.

"I'll have a look at tonight [game]. Peach did a reasonable job there… he was thrown in there at five-eighth with Jimmy doing a lot of the first receiver stuff," Griffin said. "It was nearly good enough to get us home. But we’ll have a look at it… take stock…"

For such a close result, the first try awarded to Bulldogs fullback Moses Mbye after the bunker cleared Will Hopoate of obstructing Maloney, came back to haunt the Panthers.

"The obstruction? Yes, an obstruction," Griffin said dryly, when asked his thoughts on the bunker believing minimal contact had been made.

"I'm not whinging about the result but that's why they brought in the obstruction rule, so that if a lead runner hit the inside shoulder of Maloney like that, it didn’t give him a chance to get out and they scored in the same hole.

"I thought it was a classic obstruction."

It was suggested if Maloney had taken a dive, that might have caught everyone’s attention better.

"Well that was what we were just talking about," Griffin said.

"If we have to take a dive, well that’s not good for the game and not something we want to encourage our players to do.

"But if you've got to take a dive to save a try that's what they're encouraging you to do if they let tries like that in."

Griffin perhaps has more pressing matters – leaking points early. For the third week in a row Penrith found themselves behind 14-0 in the first half.

"Can't fault our courage. When we get ourselves behind we've got a tremendous amount of team spirit… they play for each other and tonight without a halfback it was nearly a really good win there," Griffin said.

"But we've got to fix those starts and when we do that – and we will do that – it will make it a lot easier for us.''