I think he’s got another few 8 WAR seasons in him. I do. But to get to 10, he has to hit .370 again on balls in play plus see a spike in power again. Plus steal more bases. Plus be a major contributor on defense. Eventually, the smaller guys break down. Eventually, speed slows down. And his speed is what separates him from an 8 WAR player. His ability to steal bases and play GG defense in the OF is directly tied to his speed. Speed fades the fastest. Hence, he’s got maybe another 4 years to have another 10 WAR season. What are the chances in the next four years he loses no steps in the speed game, muscles up and drills 30+ bombs again and has a .370 BABIP again? Pretty damn low. That’s all I’m saying. He is a perennial 25-25 guy with almost an automatic .290-.300 BA. He’s a great, great player.
I also have touted the size as a big issue long term. Small guys fall off cliffs. They don’t age well. It’s because they cannot rely on their frames to be great, it’s all quick twitch movement that makes them great and that goes quickly. If I’m the sox GM and I look around at the league then I look at my squad, I deal him as soon as the league year restarts 5 days after the WS ends. I also don’t re-sign him after he hits the market. Remember his five years in boston fondly but don’t pay for past performance and don’t pay for a small player into his late 30s