There has been some discussion of aging current and former Twins players recently. The question is at what point does age really start to become a factor in predicting future success.
The generally accepted development curve suggests that players are likely to peak around 27 or 28. If you look at players with 300 or more at bats the largest number of players are age 27 followed by 28. About 1 in 3 of the players who got 300 at bats at age 28 will match that number at age 32. The other two thirds of players will get less than 300 at bats, because they are playing less, hurt or out of baseball.
What this means is that the General Manager of a veteran team is going to be running in place just to keep up with his teams natural tendency to get worse each year. If a team signs most of its best players to long term contracts when they are 28 or 29, they will likely find themselves saddled with a lot of underperformers before those players are 32 or 33.
This, I suspect, is one reason the Twins got rid of JD Hardy. Based on his performance in 2010 he did not look like a good gamble for the future. But it also raises serious questions about the Twin wish to sign "one or both" of Jason Kubel and Michael Cuddyer. Cuddyer is already 32 and Kubel will be past that point before any long term contract expires.
Baseball Reference has a formula for judging teams age weighted for how much players play. By their measure the Twins everyday players were the second youngest in the American League last year. Only the Royals put younger players on the field.
The Twins pitching staff, by contrast, was older than average. The pitching formula looks at starts, games and saves. Which means it may be putting too much weight on Nathan and Pavano. But if you look at the Twins rotation, Blackburn and Baker were 29, Duensing was 28, Liriano and Slowey were 27 . Those guys are moving into the downside of their careers or soon will be. None of them look like guys you want to extend long term contracts to - although they already have Blackburn and Baker under contract.
The key thing here is as I said in an earlier post, the Twins success depends on them replacing older players with younger players. There is always a risk in that. One reason teams prefer veteran players is that projecting their performance is a lot less volatile. But the price for that lack of volatility is almost certain decline.
Mauer and Morneau are both heading into decline. But they probably have a several productive years ahead of them if they can stay healthy. They may still be the core of the team. But the team isn't going to get better because they improve. That is going to have to come from young players taking other positions on the team. That means they shouldn't be adding a lot of veterans on long term contracts or resigning a bunch of their own free agents to long term contracts.