The club has issued this statement: 'United Manager Martin Ling is currently being treated for a debilitating illness. He is receiving specialist care and, while we are able to report that his is making some progress, it is anticipated that Martin will be away from work for several weeks.
'Club and the League Manager's Association are fully supportive and are looking forward to his return.
'In the meantime, United officials have held talks with assistant manager Shaun Taylor and we have agreed to actively seek an experienced coach to help Shaun with the running of the team. This process has already begun in earnest.'
More top news
Your latest West Country weather forecast with Bob Crampton.
A coroner has ruled a "series of failures" contributed to the death of a newborn.
Cornish charity ShelterBox has flown volunteers to the Turkey-Syria border to help deal with growing number of refugees there.