There are plenty of examples of players at Celtic who have continually turned out week in, week out and never take a break from first-team football. Callum McGregor is a perfect example of a player who plays almost every week for Celtic as the captain works tirelessly to continue to bring success to the team. Over the last three seasons, McGregor has missed just 28 games for Celtic and Scotland with 14 of those down to injury. Matt O’Riley and Joe Hart have been similar over the years. Prior to that, Scott Brown was another who rarely missed games for club and country during his time at Celtic…