American tall Mason Cox, has ended speculation surrounding his future, signing a three-year contract extension with Collingwood.

The new deal with see Cox remain at the Holden Centre until at the least the end of the 2020 season.

Cox was in and out of the side this season, but showed some impressive form late in the year, playing the final three matches, kicking four goals.

He managed nine games this season and has played a total of 20 matches and kicked 27 goals for the Magpies since his debut on ANZAC in 2016.

Pies' list manager Derek Hine said the club is delighted to secure Cox's signature.

“We’re thrilled that we have two outstanding ruckman in our future,” Hine told the club's website.

“The combination of Brodie and Mason is something that we are all looking forward to seeing develop.

“Mason has made tremendous progress but there is so much more to come from him, which has us really enthused about where he can take his game,” Hine said.

“He wants to learn, he learns quickly and physically he is an imposing package of height and athleticism that, combined with rapidly developing game awareness, makes him an exciting prospect.”