"He has a little dead arm," pitching coach Dave Eiland told ESPNNewYork.com. "Nothing more than that."
Yankees manager Joe Girardi raised alarms by admitting that Vazquez's velocity was down Friday when he gave up six runs, three earned, in 5 1/3 innings. Girardi said the Yankees would examine why Vazquez couldn't reach 90 mph on his fastball.
At this point, the Yankees don't believe Vazquez has anything seriously wrong. Still, Vazquez thought the Yankees may check him out further.
"I feel fine," Vazquez said Saturday before the Yankees-Red Sox game.
Eiland said the Yankees' course of action for the dead arm will be to cut down on Vazquez's workload between starts. At this point, Eiland said it will not affect when Vazquez starts.
"It is something he has to work through," Eiland said.
Vazquez's velocity is critical to his success, as evidenced by his failure to touch 90 mph early in the season, which coincided with the ugly start of his second stint with the Yankees.
Vazquez, though, has been arguably the team's second-best starter since he was skipped in May against the Red Sox. Not coincidentally, his success came with the return of his fastball.
He entered Friday 8-4 with a 3.29 ERA in his past 90-plus innings. Without being able to push the speed gun into the 90s, Vazquez struggled, giving up the six runs, including two on homers.
A "dead arm" is not that unusual for starters, but because Vazquez's success has been so closely tied with the improvement of his fastball, it is something the Yankees plan on watching closely.