Years later, Joe is still competing against players several years his senior as a pitcher for the Double-A San Antonio Missions, but he's no longer performing like someone who's at a disadvantage.
Despite just turning 21 in May, Ross, who is considered the Padres' No. 8 prospect according to MLB.com, was promoted last month to the Texas League, where the median age last season was 24.5. He responded with a 3.60 ERA and an astronomical 19 K/BB rate in 20 innings before landing on the seven-day disabled list last week with shoulder fatigue after racking up more than 120 innings in four months.
It's no surprise the Padres would want to challenge their 2011 first-round Draft pick. While spending most of this season with Class A Lake Elsinore, Ross ranked sixth in the 10-team California League with a 3.98 ERA. That figure is made more impressive after considering that California League offenses averaged a full run higher per game than National League offenses from 2008-13.
Though the mean batting average in the California League and NL during that span was virtually the same (.256/.255, respectively), the mean on-base percentage and slugging percentage in the California League were both roughly 20 points higher. That means pitchers in the Cal League generally allow more walks and extra-base hits.
But that wasn't the case with Ross, who allowed just one home run through his first 61 1/3 innings with Lake Elsinore and has a combined walk rate of 2.1 BB/9 this year.
"Walks has just been a mental focus thing -- trying to get ahead in the count early, which kind of eliminates the opportunities for walks," Joe said. "The extra-base hits, and especially home runs, is just more about pitch location. I've tried to work really hard on staying with fastballs, especially in on the hands. When batters know it's easy to hit a home run, they want to get extended and muscle the ball out. But when you keep the ball in, it's kind of hard to do that."
That's especially true when pitchers can routinely dial up their fastball to the mid-90s, as Ross can. He also has a plus slider -- like his brother Tyson, who throws more sliders than anyone in the Majors -- and a developing changeup that might be the key to his newfound success against left-handed hitters this year.
After Midwest League lefties touched up Ross for a .276 average last season, he managed to limit lefties to a .242 average with Lake Elsinore this year.
"This year my changeup has kind of come along. I think that is a big contributor to those numbers," Ross said. "When you have three pitches and you can throw them all to left- and right-handed batters, they can't try and sit on a certain pitch."
Joe was actually a member of the Padres organization before Tyson, who came up in Oakland's system. But soon after Joe was drafted by San Diego, the two brothers moved in together to a house barely a mile away from their childhood home in Berkeley, Calif., which they've lived in for the past three offseasons.
So when Tyson was traded to the Padres from the A's in November 2012, Joe was the first to know.
"He was just waking up, about 15 minutes after I had, as always," Tyson said. "He was still half-asleep, so I messed with him a little bit. I asked him, 'Hey, what's the name of the Padres' GM? Ah, well, he says hi. I just got traded to the Padres.'"
"I didn't really know how to respond at first. I was lost and still pretty groggy," Joe said. "But then later I realized it'd be cool to be in Spring Training with the same organization, and it turned out great."
This spring, Joe received an invitation to big league camp for the first time. That would seem like a prime opportunity for some sibling high jinks to ensue, but as the mild-mannered older brother, Tyson wanted to make sure Joe spent all the time he could observing how longtime professionals went about their business.
"When you're in Minor League camp, you see the big league guys in passing, but you don't know what they're really doing day in and day out and how they're preparing," Tyson said. "This year I was kind of letting him figure it out."
After all, if everything goes as planned, the Ross brothers won't be training together as big leaguers just during Spring Training.
"I think that would be really cool -- not just for our family, but for the city of San Diego," Tyson said. "And I don't think he's too far off from being one of the better younger arms in the league, up with the guys like [Jose] Fernandez in Miami and [Michael] Wacha in St. Louis. Those guys have had success, and I think he has the stuff to, too.
"Hopefully, someday he's up here with me. And that's when the pranks will begin."