The defender - United's player of the year during the 2016/17 Sky Bet Championship title-winning campaign - was also ruled out of the Republic of Ireland's friendlies upcoming against France and the USA.

But the 28-year-old former Aston Villa man is aiming to use the summer to rest and recover so he can hit the ground running for next term.

Clark told nufc.co.uk: "I had an injection a couple of weeks ago in my knee.

"Coming towards the end of the season, I'd been trying to train and doing a little bit outside but it'd not been quite right, so we took the view that we'd leave it for a couple of weeks and hopefully it'll settle down.

"Hopefully by pre-season it'll be back to normal and I'll be ready to go again for next season."

His injury and the form of Jamaal Lascelles and Florian Lejeune, who formed an excellent partnership in the second half of the campaign, restricted Clark to just one appearance after January.

But he still played 22 times in all competitions during the season, scoring important goals against West Ham and West Brom, to help United secure a top-ten finish.

"It was a great end to the season - everyone worked hard and I feel like we got what we've deserved," said Clark.

"I was injured for the last few games but on the final day we could have finished between tenth and 15th and against Chelsea everyone would have backed us to drop a couple of places.

"But the lads put in a massive effort and, especially in the first half, that was probably the best performance I saw all season from us.

"We didn't let them have a sniff, really. They had a couple of chances in the second half but the chances we created in the first half and the pressure we kept on them, they couldn't get out of their half - and they're a top side.

"We'll take a lot of confidence from that, especially going forward into the new season."