Lee gave up home runs to Juan Rivera and Edwin Encarnacion in a five-run fourth inning, and the Philadelphia Phillies lost to the Toronto Blue Jays 7-6 Thursday.
Lee, who signed a five-year, $120 million deal with the Phillies in December, has a 5.54 ERA after four games this spring.
"Spring training has a completely different feel, you have to try to make it as much like a regular-season start as you can," Lee said. "Obviously the stats aren't as important, it's more important to get your body right and work on things, experiment with stuff to prepare for the regular season, but we're starting to wind down now. I need to start being more effective."
Lee had only allowed one baserunner to reach second base in the first three innings. Lee allowed five runs - three earned - and seven hits in four innings. He has allowed six runs earned runs in his last two starts.
"The first three innings went good, the last one, not so much so," Lee said. "But it was just getting behind in the count, that was the main thing there. I got behind, had to pitch more of the plate and they got hits. That happens."
Rivera, Adam Lind and John McDonald had three hits apiece for the Jays.
Philadelphia shortstop prospect Freddy Galvis hit a two-out, two-run home run to bring his team within a run in the bottom of the ninth. Shane Victorino hit a two-run homer, his first of the spring, in the first inning.
NOTES: Phillies second baseman Chase Utley left camp with head team athletic trainer Scott Sheridan to consult a specialist in hopes of accelerating the rehab of his ailing right knee. Utley, who hasn't appeared in a game this spring, is expected back in Clearwater on Friday. Closer Brad Lidge played catch for the third straight day after getting scratched from a scheduled appearance Monday with right biceps tendinitis. Lidge will throw a side bullpen session on Friday. Third baseman Placido Polanco was out of the lineup Thursday, two days after hyper-extending his left elbow. He took groundballs during batting practice and is expected to be back in action this weekend. The announced attendance of 10,816 at Bright House Field was a new record for the eight-year-old ballpark.