Over the weekend, the Chicago Cubs and shortstop Starlin Castro agreed to a seven-year contract extension that guarantees the player $60 million, including a $1 million buyout for an eighth year option worth $16 million. While it’s expected to take another week or so to iron out some of the language in the pact, the terms of the deal will cover four years of Castro’s arbitration eligibility as a Super Two player and three years of free agency.

Having come up to the big leagues in 2010, it’s easy to forget that Castro is only 22-years-old. He’s taken a step back this year at the plate, but due to his age and increase in power numbers (even if his walk rate has declined), a long-term deal was in the best interest of a Cubs team that sold off a lot talent at the trade deadline, and only had five guaranteed contracts for next season.

We’ve suggested that Chicago had started its rebuilding period ever since Theo Epstein and Jed Hoyer were hired. The Castro signing ensures that their young shortstop will be at the center of this process, and while Castro hasn’t emerged quite yet as the star that most anticipate he will become, few teams even have the option of locking up a player of his capabilities.

The deal compares favorably to the one that the Miami Marlins gave to Hanley Ramirez back in 2008, that ensured six years of service for $70 million, covering arbitration years and the first couple of seasons of free agent eligibility. Of course, Ramirez was a little bit older when he signed his deal, and had already accumulated more than 10 fWAR in two full seasons. Meanwhile, the Colorado Rockies were able to extend Troy Tulowitzki in 2008 for six years and only $31 million. That deal, however, was signed before the player had reached arbitration eligibility, and covered fewer free agent eligible years.

Perhaps what’s most interesting about the Castro contract is that it represents an unnecessary overpay if we consider the timing with which the Cubs originally brought up their young shortstop in 2010. Yes, the team avoided losing Castro a year earlier to free agency by waiting until early May to call him up, but the team simultaneously ensured that it would have to pay an extra year of arbitration. Castro certainly proved that he was MLB ready, but unfortunately the rest of the team wasn’t ready for anything remotely resembling a playoff push. It’s hard to believe, but hindsight suggests the team might have been better off today using Ryan Theriot at shortstop and leaving the 20-year-old Castro to develop further in the Minor Leagues.

But that was then and this is now. Then was a very different management team than now. Perhaps this is best evidenced with the handling of Anthony Rizzo which proves how aware the new administration is of service time issues. The first baseman wasn’t called up until late June of this year so that he’d only accrue 100 days of service time. That’s important because in 2011, he picked up 68 days of service time with his previous team. This puts him on track for 168 days of service following the 2012 season. In order for it to count as one year, a player needs 172 days of service time for a full year, so Rizzo will fall only four days short, ensuring that he falls under team control until the end of 2018.

Like Castro, he’s expected to be Super Two eligible, but not until the end of the 2014 season. Rizzo is also 23-years-old, and a bit harder to hold back at the Minor League level than a 20-year-old, as Castro was.