Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of sporting goods retailer Dick's Sporting Goods (DKS -0.30%) plummeted 17% today after its quarterly results and outlook disappointed Wall Street.

So what: Dick's stock has struggled in 2014 on signs of slowing growth, and today's Q1 results -- adjusted EPS of $0.50 missed the consensus by $0.02 on a revenue increase of just 8% -- coupled with downbeat guidance only reinforce that trend. Management blamed the bad numbers on weak demand for hunting gear and a whopping 10% same-store sales decline at its Golf Galaxy franchise, giving analysts plenty of negative vibes over its product mix and competitive position going forward. 

Now what: Management now sees full-year EPS of $2.70 to $2.85, down significantly from its prior view of $3.03 to $3.08. "The Company expects the challenges in golf to continue throughout the year, while hunting sales are anticipated to stabilize and begin returning to normalized levels by the end of the year," said Dick's in the report. "As a result, the Company has revised its full year outlook. Given the importance of golf and hunting to the Company's second quarter, the Company expects a disproportionate impact to sales and earnings in the second quarter." When you couple that gloomy view with Dick's still-pricey forward P/E in the mid-teens, Fools would probably do well to keep watching from the sidelines.