Porcello was looking at Monday's no-decision against the Angels, who put up five runs on eight hits over 5 2/3 innings, and sounded some frustration.
"Need to go back to the drawing board a little bit and rethink what I'm doing with my offspeed stuff," Porcello said after the Tigers' 8-6 win. "Fastball is there, but I should be pitching a lot better than what I did tonight."
That has been said more than a few times this season. Leyland has been calling it a process with his 23-year-old sinkerballer, but he said some of the process could've established itself in the Minors on his way up.
For that, he blames himself and the decision he made three years ago to put Porcello in the rotation out of Spring Training.
"We brought this kid up too early, and that's my fault," Leyland said. "I'll take full responsibility for that."
Monday's issue, Porcello said, was a slider that wasn't consistent enough to get him swings and misses, or swings and outs. It was a huge pitch for him when he tossed seven scoreless innings on four hits at Tampa Bay on June 30.
Porcello had been giving up hits over the past month, but the Angels had as many extra-base hits off him Monday (four) as he allowed in his previous four starts combined.
"The slider's been a pitch I've been battling all year, not to make excuses or anything like that," Porcello said. "I got to find a way when I don't have my slider to get through games. That's what good pitchers do. I know in my mind if I get that pitch going or get some type of breaking ball going, I can have a really good second half."
Had Porcello spent more time in the Minors, Leyland said, "he would have thrown that pitch more."