Schneider's second spring homer was the Phillies' fourth straight hit in the second inning off Porcello.
Porcello said he experimented with new breaking pitches in his third spring outing.
"You want to do well, obviously, but there's also stuff you need to work on more than other things at that given time," said Porcello, who gave up his first runs of the spring.
"My previous two starts I had real good command of my sinker and got good movement on it. Today I kind of came out of a couple of them left them up too much."
Five Tigers relievers finished, with closer Jose Valverde pitching a scoreless inning.
Tigers manager Jim Leyland said the team has started the process of looking for a replacement for reliever Joel Zumaya, who has been shut down for two weeks with a sore elbow.
"I don't think from within camp, or most likely by a trade, you could replace a healthy Joel Zumaya," Leyland said. "You've got to keep looking and try to come up with somebody, most likely from within, that you can feel comfortable with. We're going to continue to look for somebody, either right or left, and see how it plays out."
Phillies starter Joe Blanton gave up two runs in four innings.
Phillies manager Charlie Manuel indicated after the game that he expects to sign a contract extension by this weekend.