On the 2009 Closer Rankings I talked about how I don't like drafting the closers during the first run usually in the 5th or 6th round. I wanted to go into what you're giving up to get that closer. I am going with the rules of a standard Yahoo league which has 12 teams and a maximum IP of 1250.
Going in the fifth round last year included Jonathan Papelbon and Francisco Rodriguez. Let's take a look at what you got in 2008 with Papelbon since his numbers are similar to K-Rod except the exceptional and unrepeatable save total. I will compare his numbers to Brian Wilson who was a late pick, had a poor ERA and WHIP, but still totaled 41 saves.
ER - 18
BB+H - 66
ER - 32
BB+H - 90
This give you a total of 14 earned runs added and 24 walks and hits added to your total.
The overall difference on a team that reaches the 1250 IP maximum is 0.10 ERA and 0.019 WHIP. The WHIP is small enough not to cause concern, but some may say the 0.10 ERA maybe enough to lose points. I will counter that the pick you gave up to get Papelbon in the 5th or 6th last year was a pitcher who makes up the 0.10 ERA and much more. The difference in strikeouts was 10 in 7 less innings which is almost nothing. CC Sabathia was averaging the pick right behind Papelbon in 2008 and supplied way more value for your team.