That's not because of anything they did or didn't do during the regular season. It's because the Detroit Tigers are such a heavily right-handed-hitting team that there won't be very many opportunities for manager Buck Showalter to match up using his lefties in the middle and late innings.
So, Showalter and his coaching staff opted for the best combination of bullpen and position depth. He'll have almost all of the position players who played significant bench and platoon roles in September, and he'll have a strong right-handed bias in the bullpen.
That shouldn't be terribly surprising, but there will be some people scratching their heads over the decision to keep Ubaldo Jimenez on the roster after a very difficult first season in Baltimore. Jimenez pitched better in two September starts, but his match-up stats against the Tigers aren't very good.
He pitched seven shutout innings in his only start against them this year, but his career stats (5-9, 4.93 ERA) vs. Detroit aren't impressive and his numbers at Comerica Park (2-7, 6.80) are abysmal.
No doubt, this has got to hurt if you're Matusz and McFarland. They deserve to be on the postseason roster – and probably will be if the Orioles advance to the American League Championship Series – but Showalter can't let sentiment get in the way of putting together a roster that best matches up against the Tigers.