The Arizona Diamondbacks may want to keep an eye on their high-priced ace.

Zack Greinke's velocity dropped into the 84-86 mph range during a simulated game on Thursday, reports Nick Piecoro of AZ Central Sports, which comes one week after the 34-year-old was in the mid-80s during a previous effort.

Greinke admitted to The Athletic's Zach Buchanan he has a nagging fear he doesn't have it anymore, though he also said he has that same fear every year.

The dip in velocity is concerning with Greinke entering the regular season as baseball's highest-paid player on an annual basis - $34.4 million, according to Cot's Baseball Contracts.

Greinke has experienced a decrease in velocity before, struggling to hit 90 mph early last spring. But the low number is still alarming with Opening Day just three weeks away.

After last spring's struggles with velocity, the 2009 Cy Young winner managed to get his fastball up to an average of 91 mph en route to a 17-7 campaign for the Diamondbacks.