Pedro Strop was the Orioles' primary setup man last year, and in terms of pure stuff, he seems perfectly capable of closing. Unfortunately, he's one of those walks-a-million types, which means the Cubs just landed themselves a cheaper version of Carlos Marmol.
Maybe they think Strop is a little more redeemable than Marmol -- and to be fair, he issued only one walk in June. Of course, he also allowed six earned runs, giving him an 11.57 ERA for the month and a 7.25 mark for the season. True, his back has bothered him at times this year, but he was also shaky over the final two months last year, posting a 5.12 ERA with 15 walks in 19 1/3 innings.
So even though the Cubs' acquisition of Strop seems to give them a clear fallback option at closer for when they inevitably trade Kevin Gregg, I don't think it's an open-and-shut case. I still think Blake Parker has as much of a shot as anybody.