The volatile closing position is nearly impossible to rate using most computer rating systems (say ESPN's Player Rater for example) because a closer's most valuable stat isn't wins or ERA or WHIP but the single category of saves . The raters also don't take into consideration the other things like the team the closers play for who else is in the bullpen to share the spot, and how likely it is that the closers will end up on the DL. Use the raters to hype players you wish to trade, but don't let it do the thinking for you.