But for Robertson that was just the beginning of a roller-coaster season that has included the biggest highs and lows of his career.
Five days later, the Padres with a logjam in AAA, traded Robertson to the Texas Rangers for cash considerations. .
The trade meant a ticket to the big leagues.
"It was a great feeling. It kind of hit me when I got traded that while it was fantastic that I was going to the major leagues at the same time it was a little disappointing that it wasn't going to do it with San Diego," Robertson said from Washington DC before Sunday's Nationals - Rangers game.
"I spent five years trying to be part of something, getting to PETCO and being part of a championship team and now that was not going to happen. But at the same time it was a dream come true to go to the Rangers and play in the big leagues."
The Rangers needed some depth in the outfield and have played Robertson at all three outfield positions and at second base, where he got his first on field game action after pinch-running the night before.
"It's funny you spend your whole career at so many other positions and your first experience is at a brand new one," laughed Robertson.
The Rangers scouts were very familiar with his game after watching him play in the Texas and Pacific Coast Leagues against the Rangers affiliates in Frisco and Round Rock.
"He's a flat out gamer," said one of Texas' scouts in San Antonio. "You know what you are going to get from him day-in and day-out and we think he can not only play all the outfield positions but we can also see him at second and maybe even third."
Robertson, who played in the middle infield in high school had sporadically been given opportunities to play the infield with the Padres in the past two years, but with the Rangers the process has been accelerated.
"It's been good especially working with Bogy [Tim Bogar, the Rangers' Bench Coach] and Wash [Ron Washington, the Ranger's manager]. We have our own little infield routine which really works on the fundamentals and has made me feel very comfortable."
"That is one of the best things about being with the Rangers, they really seem to believe in me."
After being sent over from San Diego, Robertson stuck in the major leagues before being briefly sent down to AAA Round Rock and then returning to Texas on May 20.
He was starting to get a chance to play regularly before suffering a collision in center field with right fielder Alex Rios, all six-foot-five 215 lbs. of him in right center field [Dan is listed at five-foot-eight and 170 lbs.], which caused him to suffer three fractures on the left side of his face.
"It was kind of tough because I was just starting to feel comfortable, getting some consistent at-bats and really start making some good contact."
"But you know I felt sorry myself for a few moments then started to think about all of the things I've been through this year."
Despite fracturing his face, Robertson outfitted with a special face guard for defense and for hitting, got back in the lineup on Wednesday as a defensive replacement in left field seven days later and last night had his first at-bat.
"You know for a few moments I started to feel sorry for myself and thinking why is this happening to me," Robertson said on the injury.
"But after all I've been through this year, the only thing that popped into my mind was, next."
"Because I'm coming back. I'm always coming back."