While Lloyd Saltman leads the home challenge in a share of eighth heading into the closing two rounds, Forsyth's wretched season plumbed new depths after a five-over 77 on the Stadium course left him five shots outside the cut mark with a two-over 286.
The 34-year-old, a winner in Malaysia and Madeira on the main circuit, missed 16 cuts from 31 events during a desperate campaign on the European stage in 2010 and is now facing the prospect of life on the second-tier Challenge Tour.
"This is as low as I've been in my career," revealed Forsyth, who suffered a crippling early blow when he racked up a triple-bogey 7 on his third hole. "The last 18 months have been rotten and it becomes very difficult when you are playing week in week out with no sign of improvement. I've worked harder on my game than ever before this year but I just can't find anything. There's no light at the end of the tunnel and my confidence is at rock bottom.
"You can't expect to get round a golf course when you feel like this and I don't know what to do at the moment. Hopefully I'll get a few starts next year. Having won in Malaysia and Madeira, I'll get in them but I think I'll have no choice but to play the Challenge Tour."
Forsyth was one of five Scottish tour champions to make an early exit yesterday and was joined on the high-profile casualty list by Andrew Coltart (282), Raymond Russell (286) Marc Warren (288) and Scott Drummond (289).
It is a posse that boasts eight European titles, one World Cup win and a Ryder Cup appearance among them. Coltart's departure was particularly galling after he, and fellow Scot Jamie McLeary, both rallied with four-under 66s on the Tour course to finish with two-under 282s.
That tally looked like it would make the cut on the limit until Sweden's Joakim Lagergren, playing in the very last match, picked up a birdie on his 16th hole in a 72 to push the cut mark up to three-under.
In the race for the 30 tour cards on offer, Saltman bounced back from three consecutive bogeys to post a battling level-par 72 on the Stadium course for a 10-under 274 as he cemented his place in the top-10, four shots behind Spanish pacesetter Alfredo Garcia-Heredia.
His older brother Elliot, sharing the lead after three rounds, stumbled to a double-bogey on the last in a 74 and dropped to 12th on 275 while Scottish PGA champion Chris Doak is tied for 29th on 277 after a 73. Jack Doherty, tied fourth after a third-round 63, sagged to a 77 and tumbled out of the qualifying zone on the 279 mark.