The shortstop from California's Upland High School had an operation to repair a torn meniscus in his right knee after injuring it during Instructs last fall. The A's kept him in Arizona for extended spring training and with a healthy run at Beloit, Robertson is on the verge of being fully cleared.
"The main progress we were looking to see is that he could go out there and not have to worry about that knee bugging him," said Snappers manager Ryan Christensen. "They had him on a pretty conservative schedule, but he's grown to play four games in a row with a day off now. He's right at the end of it right now and will be on his own."
That's welcome news for Robertson, who missed some much-needed development time at Instructional League four months after being drafted 34th overall by Oakland.
"It was a big deal to show them what I could do in instructs, to progress as a player and keep working on my game," Robertson said.
"To have something like that happen, it was eye-opening that it could be taken away from you like that. I lost out on an opportunity and was home having surgery. But everything happens for a reason and it makes me a stronger person."
Just weeks after being drafted by Oakland, Robertson started off with a flurry in the Arizona Rookie League, posting a .297/.405/.554 line with four homers and 10 doubles in 101 at-bats over 29 games.
He earned a late-summer promotion to short-season Vermont, where he would struggle against older competition. But although he posted a .181/.238/.234 line in 94 at-bats with the Lake Monsters, Robertson showed his potential and it proved to be a valuable learning experience.
"I've matured a lot in a year," Robertson said. "Vermont was an eye-opener for me, in what kind of hitter I am and where I need to be at in my level.
"From last year to this year, I don't think my approach has changed that much. Maybe it's just being a year older and seeing the competition from last year to this year that I've matured a little bit."
Despite having just turned 19 on March 22nd, Robertson has turned in a solid first month in the Midwest League, posting a line of .297/.346/.466 in 74 at-bats. He has two homers and 13 RBI and has scored nine times.
"I'm learning pitching sequences," he said. "At Vermont I tried to do a little too much. Now I'm trying to stay within myself. A lot of guys are going hard-in and soft-away.
"When I got out here it was an awesome feeling to get my first full season underway. Being in Beloit is all I can ask for, because we've got a great team, coaching staff and good guys. This is what I've always wanted to do."
Even with the setback last fall, Robertson hasn't doubted his decision to turn down a scholarship to UCLA and sign a contract with the A's.
"I always knew this is what I wanted to do," he said. "I wanted to get my professional career started. I've always wanted to play professional ball.
"I was raised well by my parents and they prepared me well for the professional opportunity. When my name was called on that day, it was joyful and terrific. Signing was an easy decision for me."
There's also the comfort level of playing alongside draft-mate Matt Olson in Beloit. Robertson, Olson and A's first-round pick Addison Russell, all high-school selections, have formed a close friendship in the first year of their professional careers.
"It's been me, Matt and Addison since draft day," Robertson said. "We've been good buddies. I found a place in the offseason in Arizona where we could stay for spring training and for other times we're in Arizona. It was us three living there and it was right by the facility.
"When Matt split and I was still in Arizona, it was a bummer, but I knew what the scenario was. I needed to prepare myself. Now I'm reunited with him and it feels like a good fit. We have a comfort level."
Having the opportunity to advance through the minor leagues with Olson, and perhaps rejoin Russell (who's now in High-A Stockton), is appealing to Robertson.
"I don't remember the exact year the A's took a high school [position] player in the first round, let alone draft three high school infielders with their first three picks," he said.
"I think we've got a real bright future if we all stick together. I can't even explain how cool it would be if we're all three in the big leagues together some day."