Roster building is a unique process every time it happens. Every year presents a unique group of individuals that possesses different strengths and weaknesses, both individually and as broken down by position. As a result, we often see some funny things happen when it comes to the numbers game when assembling the 53-man roster.
The 2014 Pittsburgh Steelers entered the regular season with some uncharacteristic numbers themselves, some of which were modified during the season. Such statistical anomalies are less likely to be repeated than more conventional numbers.
You expect, for example, that a team will more likely than not carry three tight ends, or eight or nine linebackers for a 3-4 defense.