Players never retire unless they're fired, but when they become 33 or older their skills start to slowly decline. So at 29 this guy has this season and the following 3 to play before his skills start decreasing.
As for the player itself, you're not doing yourself too many favours as you're practically advertising for him :P. I think he'll go for more than 300k, I would say he should end up in a 500-600k range. I would suggest that you edit your post and remove some of the info there, I'm not even sure what you're doing is allowed