Quoting: Oodz
What stats back that up LMAO
Prior to his concussion Markstrom was 10th in SV% among starters last year. Behind Backwood, MAF, Grubrauer, Vasilevskiy, Varlamov, Petersen, Driedger, Shesterkin, and Lankinen (Blackwood had only played 3 games at this point so you can choose to count him or not, I personally did).
After his concussion and up until Sutter fully implemented his system (about 15 games after becoming coach) Markstrom was 2nd last among goalies starters in SV%, only ahead of Hart.
Symptoms of concussions averagely last up to 3 months so it is very likely he was still effected by it for a while after returning to play.
Once Sutter's system was in place (using this as more of a timeline) Markstrom finished out the season once again with the 10th best SV% among starters. Behind only Greiss, Varlamov, Nedeljkovic, Fleury, Smith, Merzlikins, Saros, Rask, and Jarry (Lehner also had a slightly better record but I chose to count him as the Vegas backup even though both him and MAF played the same amount of games to end the year)