"The only thing I can really think of is the other day in Fort Lauderdale. I was thinking more about my delivery and not really how fast I was throwing," the 23-year-old left-hander said. "Today, I felt more comfortable in my delivery, which makes my arm get going a little bit quicker. That's the only logical thing I can think of."
Marlins manager Fredi Gonzalez on Monday tabbed Olsen as the No. 2 starter behind Dontrelle Willis, who will get the nod for the April 2 opener against the Washington Nationals.
While Olsen was tagged for three runs over 5 1/3 innings in a 4-2 loss to the Astros on Monday at Roger Dean Stadium, he did turn in an encouraging outing.
He threw 87 pitches, and his trademark slider was clocked from 82-87 mph. He prefers it to be from 82-85 mph, and says his 87 mph slider must have been a first-inning pitch to Lance Berkman.
Olsen is also mixing in more changeups, giving him a third pitch, which he didn't use much a year ago.
"With only a week-and-a-half, two weeks left in Spring Training, I should be getting my velocity back," Olsen said. "I've gone through the dead-arm period. Now I'm coming out of it. And we can get velocity. Velocity and my slider are usually the last two things to come for me. At least one of them is here."
As for his place in the rotation, Olsen said he wanted to be the Opening Day starter, but he fully expected the accomplished Willis to get the call.
"Is it a given that he gets No. 1?" Olsen said of Willis. "Yeah. He has the most history and the most success out of the other starters. Everybody knew he was going to start the first game."
The Marlins are going with a rotation of Willis, Olsen, Anibal Sanchez and Ricky Nolasco. A fifth starter isn't needed until April 10, and the battle is between Sergio Mitre and Yusmeiro Petit.
Hermida healing: Still a little sore, Jeremy Hermida was out of the lineup for a second straight day on Monday.
Hermida took a foul ball off his right kneecap on Saturday, and he didn't make the trip to Viera on Sunday when the Marlins faced the Nationals.
Hermida's knee is still swollen, and the right fielder is undergoing ice treatment.
Hermida had an X-ray taken on Sunday as a precaution, and the test came back negative.
"The swelling hasn't gone all the way down yet," Hermida said. "I'm just icing, icing, icing it. We had the X-ray to make sure. Everything is fine. They said, 'Just get that swelling out of there, and you should be fine.'"
Hermida is striving to be back in the lineup on Tuesday. Gonzalez didn't rule out using the 23-year-old as a pinch-hitter on Monday.
Left holding the pads: Part of being a first-base coach that is not on the job description is lugging around players' equipment once they reach base.
So it isn't uncommon to see first-base coach Perry Hill standing there with shin guards and elbow pads wrapped around his arms and legs, while his pockets are stuffed with batting gloves. Whenever a player reaches base, he will take off his extra padding and hand it to Hill.
"About four or five of our guys wear the shin guards. When they get on base, I have to hold them," Hill said. "I'm stuck with them lined up all up my arms. I look like a knight."
Miguel Cabrera wears a bulky pad on his left elbow. Cabrera will hand that padding off to Hill, who straps it on his own left arm until the inning is over.
While Cabrera has the elbow pad, Aaron Boone, Cody Ross, Josh Willingham, Mike Jacobs and Miguel Olivo all wear shin guards. Even Olsen, who had a single in the second inning on Monday, handed a shin guard to Hill.
"If the four or five guys that wear them get on base, I've got them all over my arms and legs," Hill said. "I put it on my elbow. I've got a couple of shin guards on one arm and a couple of shin guards on my other arm. I've got batting gloves tucked everywhere."
Fish bites: Olivo was hit by a pitch in the seventh inning, but he stayed in the game and ended up stealing third. ... Mitre is expected to throw a Minor League game on Wednesday, the Marlins' lone off-day in Spring Training.
Coming up: Nolasco takes the mound on Tuesday for Florida when they take on the Nationals at Roger Dean Stadium at 7:05 p.m. ET. Washington is countering with left-hander Matt Chico.