I was leaning towards Liriano myself, but I understand why anyone would go with Stroman. A lot of it, I think, is just familiarity. I think I have a better idea of what to expect with Stroman, and a better idea of what it looks like when it's Not His Day. Baltimore has struggled a bit against LH pitching this season, but I don't really see why. And the Orioles are a home run hitting team, and even in this disappointing season for him keeping the ball in the yard remains one of Stroman's strengths. On the other hand the Orioles did cuff him around in his four starts against them this season. One was good, one was bad, two were mediocre and the numbers are not pretty - 1-2, 7.04, 33 hits, including 4 HR, in just 23 IP.
Chris Tillman is one of Baltimore's two good starters (although the version of Ubaldo Jimenez who got up and walked around these last six weeks brings the number up to three.) Tillman had himself an excellent first half, ran into some shoulder problems, and got the crap kicked put of him by a couple of NL teams (Colorado and Houston knocked him around for 12 ER in just 7 IP.) Toronto's has historically Owned His Ass - he's got a 5-10, 5.44 career mark against the Blue Jays. But not this year - he made 4 starts against the Jays this season (1-0, 3.63) and they were all pretty decent - the worst was actually the one where he came away with the W.