Police are investigating an incident in the tunnel after Barnsley's match against Fleetwood at Oakwell.
Barnsley striker Cauley Woodrow tweeted that Fleetwood manager Joey Barton confronted Barnsley manager Daniel Stendel following the game, which ended in a 4-2 victory for the home team.
The tweet has since been deleted. A South Yorkshire Police spokesman said: "We are aware of something that has taken place in the tunnel after the game and we are investigating."
Woodrow, who scored in his side's victory, claimed Stendel was left with "blood pouring from his face".
Neither club fulfilled their post-match media duties after the match, which saw Fleetwood have Harry Souttar sent off after 65 minutes with Barnsley leading 2-1.
Footage tweeted by Sky Sports News showed Barton leaving the ground, but the car he was travelling in was stopped from leaving the stadium's car park.
Police stopped Joey Barton from leaving Oakwell as they investigate an alleged assault by the Fleetwood manager on Barnsley boss Daniel Stendel— Sky Sports News (@SkySportsNews) April 13, 2019
Barnsley said in a statement: "The club can confirm there was an alleged incident in the tunnel area that took place following the conclusion of today's match, which South Yorkshire police are currently investigating.
"The club is assisting the police with its enquiries and, as a result, we are not in a position to make any further comment at this time."