Robertson, 23, features a low-90's fastball and a plus curveball that he has relied on as his strikeout pitch, as well as a developing changeup. Yankees manager Joe Girardi called Robertson "sneaky" and it seems like the pitcher is ahead of the hitters -- most have yet to figure him out, but Robertson has started to get the lay of the land.
"I've never even been in big league Spring Training, so everything is new to me," Robertson said. "It's pretty crazy. You walk in and there's guys here that I watched when I was younger. I'm not saying they're old; they're just normal guys -- normal guys who make a lot of money and are great athletes."
Excepting his debut on June 29 against the Mets, Robertson has allowed one run on two hits over seven innings, walking three and striking out 11 while posting a 1.29 ERA. Overall, Robertson has a 2.00 ERA through his first seven big league appearances.
"The ball seems to get on the hitters fairly quickly, and hitters haven't seen him," Girardi said. "He's got better control of his curveball. It seemed like the first couple of days, he was jumping out there a little bit, probably because of nerves.
"Obviously, there's an adjustment, too, for young kids who come up because the Minor League balls are different than here. They have to get used to the baseball here, and that's a small adjustment that's probably not talked about a lot. It's something they have to get used to, but he's been impressive."
Robertson was the Yankees' 17th-round selection in the 2006 First-Year Player Draft out of the University of Alabama, and he comes from a talented bloodline -- his older brother, Connor, is a right-handed pitcher with the Arizona Diamondbacks.
The younger Robertson has made it to New York despite not being invited to big league camp this spring. He was 3-0 with three saves and a 1.39 ERA in 51 2/3 Minor League innings over 29 appearances at Double-A Trenton and Triple-A Scranton/Wilkes-Barre.
That performance pushed him into the Yankees bullpen, and though Girardi said that Jose Veras and Kyle Farnsworth remain the seventh- and eighth-inning combo to lead to closer Mariano Rivera, there's no telling what the future may hold.
Robertson, who has still not allowed a home run in his professional career, believes he pushed the door open somewhat for the Yankees to give him a look.
"It feels like just yesterday I was in the Minor Leagues and in A-ball," Robertson said. "Now I'm here, and it's awesome. I feel like I did everything I could to get a good look and to get a chance. You just have to get guys out."