Chiefs special teams coordinator Dave Toub confirmed the back injury as he told reporters his players needed to work on their kick returns in light of new rules and mistakes in their opening game against the Jaguars – one of the key roles Rees-Zammit is expected to take on.

“We just need to get more reps out there and make sure it’s clear what the rules are,” said Toub.

“Obviously we made a mistake in the game. It ended up costing us, but it’s a great learning experience for us.

“[It will be the] same guys that you saw. So I still want to see other guys. I want to see Rees (Louis Rees-Zammit), but he didn’t practice today. He might not be available. We’ll see, but I still want to see… there’s a lot of guys I want to see. We got time to do that.”

Rees-Zammit performed as running back, kicker and kick-returner during Saturday’s 26-13 loss at EverBank Stadium in Florida, in addition to being part of the punt coverage team.

He finished with two carries for one yard, one reception for three yards and one tackle on special teams.

Current NFL champions the Chiefs will confirm their roster on 27 August before their season opener against Baltimore Ravens on 6 September.