Wrexham boss Phil Parkinson didn't want to risk Paul Mullin

Mullin went down in the latter stages of Wrexham's FA Cup fourth round replay against Championship high-fliers Sheffield United at Bramall Lane.

Parkinson revealed Mullin was suffering with cramp and wanted to continue, with the cup tie evenly poised at 1-1, but he was substituted in the 82nd minute and the Blades scored twice in stoppage time to win 3-1 and progress to a fifth round home tie against Tottenham Hotspur.

Second placed Wrexham, three points behind Notts County in the National League with two games in hand, are left to focus on the title challenge and Parkinson insists there was no way he was going to risk his 29-goal leading marksman.

"He went down, it was a bit of cramp and there was no way I was risking him," said Parkinson.

"Simple as that, and I think our 4,700 fans totally understood that.

"He wanted to go back on and give it another go but honestly, there is too much at stake for this football club.

"If he had gone on and pulled his hamstring, it would have ruined the night because he is such a key player for us in terms of his work-rate for the team and his tactical understanding without the ball but obviously his goalscoring is key to it - any team needs goalscorers.

"There is no way I could risk him and hopefully we got him off in time, and he will be fine for the weekend."

United took a 50th minute lead but Mullin converted a penalty to make it 1-1 and the striker could have put Wrexham ahead but his second spot-kick of the night was saved by Adam Davies

Parkinson felt Mullin caused the Blades lots of problems over the two games, with the striker also scoring in the 3-3 draw at The Racecourse.

"Mulls scored the first penalty great and he hasn't managed to convert the second one," added the Reds' boss.

"But over the two games, Mulls has given Championship/Premier League defenders a really tough time and that is enormous credit to him."