The League One club said they are working with South Yorkshire Police and assisting with all enquiries.
Woodrow later deleted the tweet.
On Monday, South Yorkshire Police said they were continuing to investigate reports of an assault at Barnsley Football Club.
"No arrests have been made at this time and enquiries remain ongoing," a statement added.
Fleetwood said they had "been made aware of an alleged incident" and were "currently establishing the facts".
BBC Radio Sheffield reported on Sunday that German Stendel, 45, was "OK" but "suffered facial injuries".