Rafa Benitez runs through Newcastle United's injury problems

Benitez's side won last night's third-round replay 4-2 to book a home fourth round tie against Watford.

United, however, lost three players over the two games against the Championship club.

Midfielder Jonjo Shelvey aggravated a thigh injury after coming off in the first game, while defenders Jamaal Lascelles and Ciaran Clark limped out of the replay.

"There were a lot of positives, and the negatives were the injuries," said manager Benitez. "We will see how bad they are. We are in the next round."

Clark suffered a knee injury in the first half and was replaced at the break by Lascelles, who pulled up clutching his hamstring seconds after coming on.

Lascelles, Newcastle's captain, tried to play on, but lasted just 10 minutes.

The pair are being assessed, along with Shelvey and defender Paul Dummett, ahead of Saturday's Premier League home game against Cardiff City.

"We have to wait and see how they are," said Benitez. "Ciaran Clark has a knock in his knee. Jamaal, it seems, was feeling his hamstring.

"We will see. It seems that it was not very serious, but he couldn't carry on. In a couple of days we will have a better idea. At the moment, it's too early.

"(Isaac) Hayden was fine, he had a kick in his back. Shelvey and (Paul) Dummett, we have to wait."

Meanwhile, winger Kenedy wasn't involved against Blackburn because of a problem with a nail.