Centre Clarke missed last week's promotion-clinching win over Exeter that saw Northampton Saints claim the National League One title earlier than any team since Richmond in 1989.

And director of rugby Jim Mallinder revealed the injury-jinxed 24-year-old is possibly out for the rest of the season.

After missing virtually the whole of last season with a broken ankle, Clarke has been slowly getting back to his best with a strong run in the side.

But after helping Saints win the EDF Energy National Trophy semi-final at Plymouth, Clarke now has medial ligament damage in a knee that might yet need surgery and is out of tomorrow's league clash against Nottingham.

That could mean he is also now out of Saints' EDF Energy National Trophy final against Exeter in two weeks time.

Mallinder said: "Jon Clarke has had this ongoing problem with his knee, it has not been 100 per cent.

"We are just looking after him to be honest, that's the position we can be in fortunately.

"We don't have to force players into playing, we can make sure they are right for the long run.

"You don't have to force players into playing now. It possibly is the end of his season."

Meanwhile, Mallinder confirmed Christian Short is moving to Brive and says he is now on the lookout for an experienced lock as a replacement.

"Christian has got an option to go out to Brive and we've decided that it is right for him and right for us to let him go," he said.

"This year Alex Rae has become our main lineout man and we are delighted with how he is playing.

"It is an area where we probably need a little bit more experience in. We've got some really good potential coming through, so we're delighted at that.

"But losing someone like Christian means we probably need to look to bring in a replacement."