Northamptonshire boss David Ripley has said the County Championship Division Two promotion race could be heavily influenced by the next four weeks.
Top side Northants play four first-class matches before the end of June.
"I think Hampshire will be there. They're a big club with decent resources and I think they'll be in the shake up, as will Lancashire," Ripley told BBC Radio Northampton.
Monday's 36-run win over Warwickshire was Northants' first YB40 victory at home for two years, when they beat Scotland by four wickets.
"We've got both sides in the next block so it's a very exciting four weeks."
Ripley's men host Hampshire at Wantage Road on Wednesday before four-day fixtures against Worcestershire, Leicestershire and Lancashire, as well as YB40 games with Kent and Sussex.
It is a heavy schedule for Northants who rested all-rounder David Willey for
Monday's YB40 win over Warwickshire.
Andrew Hall, who scored one with the bat against Warwickshire, could also be given a breather, while bowler Trent Copeland has two County Championship games
remaining before he ends his Northants spell.
"It's nice when the games come thick and fast because you get a bit of rhythm. But it will be quite tough physically," said Ripley.
"We've talked a bit about rotation and I think we'll have to look at that.
"We can't keep sending out the same guys in four-day and one-day cricket and expect them to get through a whole cricket season.
"We're expecting David Willey to be fit [for Hampshire]. Andrew Hall's played every game, Trent Copeland's played every game and we have resources we haven't yet tapped into."