"The velocity obviously isn't there. Being my fifth start, I feel I've made a lot of progress, but just have got to continue working and get a lot better," Matusz said after giving up six runs, nine hits and three homers in 4 2/3 in Saturday's 10-5 loss to the Reds.
Matusz said the decreased velocity has left him with a smaller margin for error.
"Absolutely. Not being able to pitch with 93, 94 like I have in the past, you've got to be able to have a better plan and execute pitches better, especially with their big hitters," he said.
"It's a matter of building arm strength."
Matusz still tried to find a positive or two from his 87-pitch outing.
"I took a lot from this outing. Went out there with a game plan and made some good pitches. But I let their best guy in the lineup hurt me today. Can't let that happen," Matusz said.
"My stuff has gotten better, a lot better. Good feel for the changeup today. Made some nice pitches some times when I needed, but I need to bear down better with their tough hitters."
Joey Votto hit a two-run and a three-run homer off Matusz and Jonny Gomes added a solo shot.
"Bad locations, very bad locations to quality hitters," he said. "With Votto, there are not many guys in the league that will hit a 3-2 curveball like that from a left-hander over the right-field wall. Just gotta be in a better location and not put myself in that situation to allow him to see so many pitches."
Matusz has now allowed 14 earned runs and 20 hits, including six homers, over 11 1/3 in his last three starts. He is 1-3 with an ERA of 6.85 through five starts after finishing last season 6-0 with a 1.57 ERA over his final eight starts.
"You learn so much more from failures than you do from having success. Just a matter of getting better every day and learning from it," Matusz said. "It's a matter of being able to make better pitches. You can't let the better hitters hurt you and that's what I've done."