Olsen, who is recovering from left shoulder surgery, lasted 4 1/3 innings and gave up all six runs on 12 hits. The good news was that the velocity on his fastball was clocked as high as 91 mph, although manager Jim Riggleman was told by a team official that a different radar gun had Olsen at 89 mph.
In his previous start in a Minor League intrasquad game, Olsen's fastball was clocked at 86 mph, even though he didn't give up an earned run in four innings.
The organization grew concerned after that game, and it got to the point where Riggleman indicated Monday that Olsen was no longer a lock to be in the rotation. After Tuesday's game, however, Riggleman thought Olsen threw the ball much better.
"I thought that it was the best he has thrown," Riggleman said. "That gun out there in center field may be a little bit higher, but I thought the ball was coming out of his hand well. He just looked freer with his arm. The results weren't good."
Said Olsen about his velocity: "I don't know what to make of that. I don't know how I was throwing 86 mph five days ago and I don't know how I was throwing 91 today. I don't know. It is what it is. I guess we are getting stronger. I feel fine, no pain. It was free and easy for the most part. I don't feel tired or anything."
In the first three innings, Olsen had given up a run on six hits, but he was a victim of below-average defense. However, by the fifth inning, Olsen didn't have anything left in the tank. He allowed two runs in the fourth and three in the fifth.
"The first four innings I'm pretty happy with," Olsen said. "The fifth inning really fell apart. That can't happen. I will try to build off the positive things earlier on in the game and learn from the bad things that happened in the later innings."
Olsen has two more starts to show that he still belongs in the rotation. He is competing with Livan Hernandez, J.D. Martin and Craig Stammen for the final two spots in the rotation.
"I feel good. I feel like I'm getting close," Olsen said. "Hopefully, I'll be stronger in five more days."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.