It might be something that changes after internationals but this happened last season as well Matic had a slump from around this time through to maybe March when he seemed to get his act together again.
There is an element of him being the latest in a line of many targets he's this weeks problem and in 3 week's time he'll be the solution he's not the only problem we have but it would be nice to see Fred being bedded into the team from the start.