The German international is rated as one of the top keepers in the world and Alex Ferguson is said to be interested says Thomas Kroth.
"I have read the reports about Manuel and a possible transfer to Manchester," he said.
" I can confirm that United are interested in securing his services."
Sir recently suggested that one of Edwin van der Sar's understudies - either Ben Foster or Tomasz Kuszczak - would replace him when he decides to retire.