Starlin Castro is six months younger than George Springer, the Houston Astros' top prospect who made his MLB debut in April.
Here's another: At 24, Castro is only 22 months older than Kris Bryant, the other-worldly Cubs prospect who is tearing it up in Double-A right now.
As Castro continues to learn and grow in his fifth season in the big leagues, those facts serve as a nice reminder to temper expectations on the Cubs shortstop and building block. After all, he racked up 692 hits in 606 career MLB games before his 24th birthday.
So when Castro goes through slumps like he did earlier this month - he began June mired in a 3-for-21 stretch - it's important to look at more than just his batting average.
This season, Castro has worked to climb out of his slump by being proactive - watching more video and working with Cubs hitting coaches Bill Mueller and Mike Brumley.
"That's part of his growth; that's part of him growing up," manager Rick Renteria said Sunday before the Cubs-Marlins series finale. "I would say he's been proactive his whole career. But you have to know how to be proactive. You have to know what to look for and you need to know how to be able to ask the right questions."
A good teaching moment came up just hours after Renteria talked about Castro's work behind the scenes.
The shortstop - who has been hitting fourth for the Cubs for most of the season - came up with the bases loaded and one out in the seventh inning of a tie game with the Marlins. Castro got too impatient and flailed at a pitch out of the zone, striking out and failing to drive the run home.
Renteria admitted Castro was a little bit overeager.
"Those are the situations in which, over time, we can have a conversation with him to see where he was maybe accelerating his emotions," Renteria said. "Those are the things that hitters, in those situations, have to try to control."
After struggling through a rough 2013 season in which he hit only .245 with a .631 OPS, one of the main storylines heading into the 2014 campaign was whether Castro would bounce back.
If you just look at his batting average (.273), it wouldn't appear as if he's taken much of a step forward, but that doesn't tell the whole story.
The two-time All-Star is hitting the ball with more authority, on pace for a career season in slugging percentage (.447), doubles (on pace for 46), homers (20) and ISO (isolated power - .174). Castro is also hitting more line drives (22.7 line-drive percentage, up from 20.3 career mark) and fewer ground balls (44.1 percent, down from 48.9 career mark) while also walking at his highest rate (5.6 percent) since his rookie season.
So while he may be getting fewer hits than the .297 average he posted during his first three years in the big leagues, Castro is making his plate appearances count more this season.
That's exactly the progression the Cubs wanted to see from their franchise cornerstone.