Tonight, the Orioles entered the ninth inning with a two-run lead. Due up for the Mariners were two right-handed hitters and a switch-hitter. The Orioles' pitcher was Chad Bradford, who is extremely effective against right-handed hitters but bad against lefties. Their "closer" is George Sherrill, who is just the opposite: murder on lefties, but ineffective against righties.
What did manager Dave Trembly do? I think the answer is obvious, or I wouldn't be writing this.
Bradford wasn't too tired to go back out there. Did Trembley pick Sherrill because he gave Baltimore the best chance to win? No, it happened because Sherrill is the "closer" and this was a save situation.
There's nothing wrong with giving up the platoon advantage to put Jonathan Papelbon or Mo Rivera out there to close out a game, but when you take a lefty specialist (in relief of a righty specialist!) and let him face three right-handed batters just because of his job title, you're actively hurting your team's chances. Better to have no designated closer at all than to use him in this way.
Of course, the Mariners went down 1-2-3, so Trembley will make this same mistake next time.