I don't see much of a problem with the guy, if you don't like him cut him, I am in d3 in that world, I'd gladly take him. I would not hesitate to start him all 4 seasons at SF, I looked at your team, he only has to be the backup for two seasons, then can start for two from what I can tell, perfect really. My lakeland team has a player like him, only my guy is much worse, he has been a backup SF for 3 seasons now, he is only a 10 rebounder, but has very good defense and ath, also he was a single digit in PA / PER when I recruited him, he has improved since then some, but the improvement has really had no effect on his stats, he is not out there for offense - I did not this season, but his first season I did a plus / minus for when he was on the floor for about 8 games, he was more positive than my team was, although teams like mine tend to do well in mop up time, so that may be misleading - but certainly no cause for alarm, players like him are the reason we are given control of distro - when I coach real life, I often start a player like him, although I tend to think speed and defense track more closely real life than ath & def, but I appreciate the sentiment of linkage of something to defense like speed or ath - take a look at the player I am describing:
http://whatifsports.com/hd/PlayerProfile/Ratings.aspx?tid=7797&pid=1772618