Unfortunately for Jordan McLean, when it rains, it pours. Just a matter of days ago, the in-form Cowboys prop was preparing to finally make his Origin debut for the Blues at nearly 31 years-old. Now, McClean will be racing the get a few games under his belt before the finals.

McLean suffered a hamstring injury during a New South Wales training session earlier this week, handing Jacob Saifiti his maiden sky blue jersey instead.

Originally named to replace the injured Payne Haas, McLean followed in the foot steps of other candidates Reagan Campbell-Gillard and Dave Klemmer in making their international debut before Origin, though McLean will remain the only one without a jersey.

Scans have come back worse than originally thought for McLean, who has suffered numerous hamstring injuries throughout his 168 NRL-game career. Results have shown the injury to be Grade 2, meaning the North Queensland enforcer will miss at least 3-4 weeks, and won't join fellow Cowboys Tom Dearden and Tom Gilbert as debutants on Wednesday night.

While he will still watch on in support, it's unlikely we'll see McLean back on the park until the Cowboys Round 21 clash with Canterbury in Bundaberg. Deep in the top four, it's hard to see Todd Payten risking a hamstring injury so close to the finals.

His injury couldn't come at a worse time for the Cowboys, who recently lost Heilum Luki for the season with an ACL tear, while Queenslander Reuben Cotter isn't expected to return until Round 22.

The Cowboys are yet to release a statement following the scan results.