The return of supporters to the County Ground was ruined by the elements, as events were called to a halt on Sunday afternoon with Lancashire 88 for one in their first innings.
Both teams claimed eight points from the drawn fixture, but Northants now face a huge task to try and claim the top two finish that would see them compete for the LV= Insurance County Championship title in the end of season play-offs.
Just 34.3 overs were possible over the whole four days of the fixture, with heavy rain playing havoc and ensuring day two was a complete washout on Friday.
"The weather has beaten us," said Rossington.
"The ground-staff have been fantastic doing their best to get us on when they could, but just one of those things."
Northants remain in fourth place in Group 3, but with just four matches remaining they are still 22 points adrift of second-placed Yorkshire.
The County travel to Hove on Thursday to take on Sussex, and know that is now a game they are going to have to win to keep alive their title hopes, but it is a similar story for Sussex who are fifth, 12 points behind Northants.
"I think the closer we get to the end of this section of the competition teams might be trying to set up some run chases to get results," admitted the Northants skipper.
"We have got to get first innings runs which will be the key to setting up those games."
Lancashire skipper Dane Villas was equally frustrated at the weather of the past four days.
"It’s terrible when you come to a ground like this, see such a nice pitch and then you don’t get much cricket on it," he said.
Another disappointment for the fans was the fact they didn't get to see England legend James Anderson bowl, and Villas said: "Guys like Jimmy needed overs.
"That was the main thing for him going towards the Test match.
"We now won’t have Jimmy against Yorkshire – he’ll be back in the England bubble on Friday, but we have a good stable of fast bowlers who as always have learnt a lot from him."