The 27-year-old Switzerland international only managed to play 80 minutes of the 3-1 loss to Liverpool on Saturday as he was subbed off due to picking up an injury.
Newcastle boss Steve Bruce shared after Saturday match that the club were hoping Schar just suffered from cramp rather than his pain being a result of him tearing his calf.
“It’s the calf, we’re not sure if it’s cramp or a tear,” he said, as quoted by the Chronicle.
“The medical department say he does suffer from cramp a little bit.
“We do hope it’s that.”
However, Mills admitted that he was worried about Schar potentially missing games after watching him depart the pitch early on Saturday and claimed the defender would be a big miss for the Magpies.
“When you miss good players, (you miss) not just their ability to be good defenders; leadership qualities, organisational qualities, all these things are what you miss more than just the actual player.”
While Bruce has experienced defenders such as Federico Fernandez and Ciaran Clark waiting in the wings to feature if Schar needs to drop out of the starting line-up, Mills is spot on to worry about how the Magpies could potentially cope without Schar.
The 27-year-old has been in fantastic form this season already as he has averaged 2.6 tackles per game, 2.8 interceptions per match, four clearances and has even managed one block per game on average across his five league appearances. (Source: WhoScored).
Schar has averaged a higher rating than his current central defensive partners Paul Dummett and Jamaal Lascelles across the first five league games and has proven to be a useful asset when it comes to going forward as well.
The centre-back has contributed one goal to the cause and has even averaged 1.2 shots per game, which is the same as Magpies attacker Miguel Almiron. (Source: WhoScored)
So when you consider how good Schar is, and the fact he is a player capable of contributing at both ends of the pitch, Mills is spot on to worry about how the Magpies would cope without him if he is set to miss games.
This is the case even if Bruce does have cover when it comes to his defence.