Toronto FC announced Friday that defender Drew Moor will not be travelling for a weekend clash against the Columbus Crew after a medical exam revealed a cardiac arrhythmia.

The heartbeat irregularity was discovered during a medical examination following a training session earlier in the week and the club said Moor will not travel to Columbus as a precautionary measure.

A heartbeat irregularity was responsible for Clint Dempsey missing around five months of action for the Seattle Sounders last season, but Toronto FC has not specified the extent of Moor's diagnosis, explaining in an issued statement to media that, "Further testing is necessary to determine diagnosis and management, which will take place next week."

Moor's absence will be a blow for Greg Vanney's side as the veteran center-back, 33, has been a vital part of the starting lineup since joining the club in 2016. He has played every minute of Toronto's 2017 campaign and formed the foundation of a back-three alongside Nick Hagglund and Eriq Zavaleta.

In his stead, Vanney can call upon Chris Mavinga, but he was not too impressed with the young French defender after last week's 2-2 draw against Atlanta United, telling reporters Mavinga was "way too slow to read the action and see what was going on."