Aberdeen captain Mark Reynolds suffered a broken nose in a 1-0 win over Hearts that consolidated second place in the Scottish Premiership.
The 28-year-old did not appear for the second half after a clash of heads.
And fellow defender Graeme Shinnie needed stitches for a cut head after catching a flailing elbow from Hearts striker Osman Sow.
Dons boss Derek McInnes said: "It was a bit niggly and it was hard for the referee to manage the game."
Six players, four from Hearts and two from Aberdeen, were booked in what was a bruising encounter between second and third at Pittodrie.
Hearts midfielder Miguel Pallardo was substituted by head coach Robbie Neilson in the first half before the Spaniard could get himself sent off.
McInnes had sympathy for Thomson but was delighted to see his side were not going to bullied out of a win that makes it 13 points from the last 15 available.
"There was a good bit of composure about us, but I thought it was a wee bit scrappy and a wee bit stop-start in the second half," he told BBC Scotland.
"There are a few cuts and bruises in the dressing room, but you expect that as it's two teams wanting to win and challenges have to be made."
Aberdeen, who move to within a point of Celtic ahead of the leaders' Sunday trip to face St Johnstone, were the better side in the first half.
However, it was not until an inexplicable late hand ball by Jordan McGhee that the Dons were able to take the lead from Adam Rooney's penalty.
"I thought Hearts had a decent spell in that second half and showed a bit more of what they have about them," added McInnes.
"They showed they are a good team, so we had to show some perseverance to get the goal.
"We got the break even though it came from a mistake by their defender, but Adam Rooney still had a job to do.
"He did it as well as he always does and I don't think anyone can deny that we deserved the win and the three points."