Celtic manager Brendan Rodgers has urged referees to do more to protect his players from dangerous challenges.
He believes Kieran Tierney could have been seriously injured by a tackle against Motherwell last week and wants officials to punish recklessness.
"The concern for me is the ones that are late, the one like last week that was a straight-leg challenge that could have really damaged him," Rodgers said.
"That's the duty of the referee, to protect the players, and the game."
Rodgers was concerned by Ryan Bowman's challenge on Tierney, for which the player was booked, and one on Scott Sinclair against Inverness the previous weekend.
The Celtic boss has not yet spoken to the Scottish Football Association's head of refereeing, John Fleming, but says he will if the issue is not addressed.
Tackle on Tierney 'horrendous'
"My only worry at this moment is protection for my players," Rodgers said. "I've seen two tackles in the last two games that weren't good tackles at all.
"The tackle on Kieran Tierney was horrendous.
"This is a kid who's coming through, he's 19, one of the great prospects of Scottish football. I've a boy who's a brilliant coach on my staff, John Kennedy, who was also a brilliant prospect who in one challenge lost his career.
"I don't want that to happen to any of my players, or any player, whether he's from Celtic, Rangers, Hearts, Hibs, wherever.
"I understand there's maybe a dimension of wanting to get tight to Scotty Sinclair, to put a challenge in, but it's the responsibility of referees to protect the game and the players.
"If we're trying to have the best players in Scotland, they need a little bit of protection.
"We're a team of men and we're playing a man's game, so we've no problems with aggression and we've coped with that. You want the competitive games, you want the aggression, with passion, but it needs to be within the law."
'Gordon deal nearly there'
Rodgers said that contract talks with goalkeeper Craig Gordon are continuing and remains confident that the 34-year-old, who was the subject of interest from Chelsea during the January transfer window, will reach an agreement.
"Between his agent and the club, it's ongoing," Rodgers said. "These things take a little bit of time and we all want it resolved as soon as we can.
"Craig is very happy and it's nearly there. There are always details that need to be closed out by both parties.
"It's certainly not stalled. This is a very important contract for Craig, and it's important for the club. You have to respect the club's position as well.
"You don't just snap your fingers on these thing and they happen overnight. I'd be very hopeful that it's resolved soon."