Perhaps more than any other sport, baseball loves its clichés. No matter how long you've been a baseball fan, you've likely heard them uttered with great frequency, ranging from the likes of "pitching wins championships" to the more humble "it's a game of inches."
While some of these clichés are more true than others, there are also a few that just don't stand up to scrutiny, and perhaps no time-honored cliché is more wrong than the old adage "speed never slumps."
On the surface, the statement actually makes sense. Speed is certainly a skill that one either does or does not possess, and it's not likely to have much variation from day to day. You're either fast or you're not.
However, the idea behind the "speed never slumps" slogan is that a team can avoid inconsistent performance by stocking up on a roster full of players who create value with their legs, rather than relying on just their bats to carry the day.
However, as the career of Nyjer Morgan has shown, being fast doesn't offer any kind of guarantee of consistency.