Tigers reliever Brayan Villarreal ended up being the odd man out. He posted a 2.63 ERA in 50 appearances this year but did not pitch as well in the second half.
For Oakland, left-hander Brett Anderson is on the roster after missing the last couple weeks of the regular season because of a strained right oblique.
Anderson has made only six starts this year -- all between Aug. 21 and Sept. 19 -- and went 4-2 with a 2.57 ERA. He missed most of the season recovering from elbow surgery.
The Tigers are carrying 11 pitchers and there was speculation Porcello could be left out since he's not part of the starting rotation for this series, but both he and Smyly can be options to pitch in long relief.
The Athletics have 12 pitchers, six infielders, five outfielders and two catchers on their roster for the division series, which starts Saturday night. Oakland reliever Pat Neshek, back with the team after the death of his newborn son, is on the roster.
Information from The Associated Press was used in this report.