Krul looked in agony after falling awkwardly on the artificial turf near the end of a match he was only playing in because the Netherlands' first-choice keeper, Jasper Cillessen, pulled out during the warm-up.
Newcastle, bottom of the league after eight matches without a win and having conceded 17 goals even with Krul in the team, are likely to hand the gloves to Rob Elliot for the visit of Norwich City on Sunday.
"It's a bitter blow for Tim and for us," McClaren told the club's website (nufc.co.uk). "I spoke to him on the morning of the game he wasn't playing and, selfishly, I thought that was good, because then he would be fit for us.
"Then I got the news, the severity of the injury and how he did it, and it's a massive blow.
"Tim is a big part of us -- he's a big player, a leader in the dressing room, and his goal was to establish himself in the Dutch side going forward.
"We will miss him for the rest of the season, and he loses seven or eight months of his career."
Newcastle have recalled 18-year-old Freddie Woodman from a loan spell with fourth-tier Crawley Town as back-up for Elliot.
McClaren said he was confident Republic of Ireland international Elliot would handle the pressure.
"I've been impressed by Rob from day one when I came into the club," McClaren said.
"He's very vocal in the dressing room, is a senior player with good experience and is not afraid to say things.
"That is vital, and this situation gives Rob an opportunity to show what he can do."
(Reporting by Simon Jennings in Bengaluru; Editing by Peter Rutherford)
Share
