The reason that age is listed as prime years is because players' most productive seasons generally coincide with those ages. Players tend to improve up until around 26 or so, they peak sometime in the 26-29 range, plateau in the 29-30/31 area and decline starting in their early to mid 30's. Soriano, at 31.5 years, is likely to be a guy whose numbers have seen their heights and will begin to pull back. Of the names you listed, DLee put up his best numbers at age 29, he's far off that pace now and likely will never return to that pace. Jeter's best year was at age 25, he's fluctuated quite a bit since then, but he's probably not going to be returning to his best numbers. Vladdy's best year was at age 26, he's flirted with those numbers since then, and he is again this year, but again, we're probably not going to see him best those numbers. Hunter has been very inconsistent from year to year. He's on pace to have a career year, but he's no guarantee to maintain those numbers. Alex Rodriguez is the best player in baseball. His best years were between 24 and 29, with the two best seasons coinciding with each of those ages. He's on pace to eclipse those numbers this year, but there's a lot of time to play. Soriano doesn't compare with ARod if you want to talk about guys capable of sustaining greatness. When somebody talks about the Cubs best players being in the prime of their careers, they are really reaching. Soriano is past his prime years. He may pull out a career year sometime in the next few years. But by and large, you can count on his age 31-35 seasons to be a step off what he did from 25-30. He's not in his prime. This isn't just made up nonsense by people who want to pick on the Cubs. Players are at their best in the mid to late 20's, while pitchers are a couple years later. Truly great teams, like the late 90's Yankees, with great players like Williams, Jeter, Posada, Tino, Knoblauch, have studs in their 20's and can sustain winning over a long time. If your best players are in their 30's already, you better win now, because contrary to what the original post insinuated, the Cubs best days are not ahead of them, not with Ramirez already at 29 and Lee and Soriano in their 30's. They will need an influx of great younger players if they want that window to stay open.