Sample size and quality of competition, but it's interesting and slightly concerning.
It's not all that uncommon, actually.
ANA
Hiller - 45 GP, 27-11-6, 2.40 GAA, .914 SV%
Andersen - 22 GP, 16-4-0, 2.22 GAA, .925 SV%
LAK
Quick - 39 GP, 21-15-2, 2.10 GAA, .914 SV%
Jones - 16 GP, 10-5-0, 1.90 GAA, .932 SV%
Scrivens - 19 GP, 7-5-4, 1.97 GAA, .931 SV%
NYR
Lundqvist - 53 GP, 26-22-4, 2.50 GAA, .917 SV%
Talbot - 19 GP, 11-6-0, 1.76 GAA, .937 SV%
PHX
Smith - 59 GP, 26-20-10, 2.67 GAA, .915 SV%
Greiss - 15 GP, 7-5-1, 2.25 GAA, .927 SV%
SJS
Niemi - 55 GP, 34-14-6, 2.34 GAA, .914 SV%
Stalock - 20 GP, 11-4-1, 1.91 GAA, .931 SV%
WSH
Hotlby - 41 GP, 19-14-3, 2.98 GAA, .911 SV%
Grubauer - 17 GP, 6-5-5, 2.38 GAA, .925 SV%
Neuvirth - 13 GP, 4-6-2, 2.82 GAA, .914 SV%
WPG
Pavelec - 52 GP, 20-24-6, 2.97 GAA, .902 SV%
Montoya - 23 GP, 11-6-3, 2.18 GAA, .924 SV%
On most other teams, their starter and backup are only a few percentage points apart. It's actually more rare for the starter to be significantly better statistically than the other way around - at least, as far as this season goes.