Northants have failed in a bid to sign New Zealand all-rounder Tim Southee.
The 27-year-old would have joined as temporary overseas cover for injured South African Rory Kleinveldt.
Southee has played 48 Tests, 99 one-day internationals and 38 Twenty20 games.
"We were very hopeful of having him from 1 July, but it wasn't signed off by New Zealand Cricket. They have tours ahead of them and it's their priority, but we really thought this was going to happen," said head coach David Ripley.
"The big downside is another week has ticked by now, which leaves us short of time to get someone in."
Kleinveldt, Richard Levi, Olly Stone, Steven Crook and Monty Panesar all sat out Northamptonshire's County Championship game with Sussex this week.
In addition, Seekkuge Prasanna is currently playing for Sri Lanka in their one-day series against England.
"We get Seekkuge back after that series which isn't far away, but Tim would've been great," Ripley continued to BBC Radio Northampton.
"He wanted to play red-ball cricket and is obviously an Indian Premier League player too. But it wasn't to be.
"We've still got a couple of irons in the fire and are hopeful of getting someone in."