The 25-year-old was on the end of a rash challenge from Wycombe Wanderers midfielder Marcus Bean, where scans revealed he is set to miss the next eight to 12 weeks.
Watmore had only battled back from a second ACL injury of his career late last year and scored his first goal in a Black Cats shirt since his return at Adams Park.
However, his dramatic late leveller was met moments later by an awful challenge by Bean, providing another slice of horrible luck for Watmore.
Portsmouth attacker Ronan Curtis has been involved a freak accident after chopping the top of his finger off.
The incident occurred on Monday morning when a gust of heavy wind slammed a door on the Irishman’s finger at his Southsea home.
The 22-year-old had been preparing to meet his team-mates to head to Walsall but instead remained on the south coast to undergo plastic surgery and reattach the top of his finger.
Peterborough United manager Darren Ferguson has criticised referee Ollie Yates after a late penalty inflicted a 1-0 defeat at AFC Wimbledon.
The 47-year-old believes Posh were “beaten by a terrible penalty decision” as Ferguson slipped to fifth defeat in his opening eight games since returning for his third spell.
Posh are likely to appeal the decision after Rhys Bennett was shown red for denying substitute Dylan Connelly a dubious obvious goalscoring opportunity.
Bristol Rovers boss Graham Coughlan has backed Jonson Clarke-Harris to become a Championship player in the near future.
The Gas striker, signed on January deadline day from Coventry City, fired his sixth goal in seven matches last night with a stunning strike from 25-yards.
It helped Rovers overcome Gillingham 1-0, and Coughlan believes Clarke-Harris may soon be moving up the football pyramid.
“I keep saying to Jono you have to work hard and do the basics,” he told Bristol Live. “Get that consistency in your game and you won’t be playing in League One any longer.
“Jono keeps saying he wants to play in the Championship with me and I keep telling Jono, and I have been promising all his days, I will help him get there. I hope that is with this club.”
Newcastle United and Southampton are chasing MK Dons wonderkid Recoe Martin, dubbed as the new Dele Alli.
The duo, alongside Norwich City, are casting an eye over the 18-year-old after he scored five goals in 17 minutes as MK’s U18s came from 2-0 behind to beat Leyton Orient last week.
Martin is yet to sign a pro contract with the League Two promotion-chasers and could leave on a compensation package - which makes him an even more attractive prospect.
Since Alli’s move to Tottenham Hotspur in 2015, The Dons have gained a reputation for producing home-grown youngsters.