"I'm a big scaredy cat when it comes to needles," said Gallagher, a Padres reliever who was the player to be named in the Scott Hairston deal with the Oakland A's in July.
"I can get tattoos for hours, but I just can't do needles. I don't have any idea why that is."
Gallagher discovered just how edgy he was with needles earlier this summer when he had platelet-rich plasma therapy to help repair a slightly torn patella tendon in his left knee.
The procedure, still considered a relatively new medical approach, helped get the right-hander on the track toward resuming his season.
The procedure occurred when Gallagher was still with Oakland's Triple-A affiliate in Sacramento. Gallagher was trying to field a ball down the first-base line and his knee all but buckled on him.
"It just gave out on me," he said. "I wasn't sure what I was going to do."
Luckily for Gallagher, Sacramento head trainer Brad LaRosa was familiar with platelet-rich plasma therapy. He suggested it to Gallagher, who made a few calls around, having never heard of such a procedure.
"It's still fairly new," Gallagher said. "I called around and a lot of guys had either heard a little about it or not at all."
The procedure took about eight ounces of plasma from Gallagher's arm and placed it in a centrifuge. That produced concentrated platelets -- which contain growth factors that accelerate tissue repair and regeneration -- that were injected into his left knee.
"I guess the natural antibodies of the body help the healing process," Gallagher said. "It's been shown through tests that the plasma helps the healing process up to 700 percent.
"There was pain. The pressure that you feel from the amount of fluid they inject in there is tough."
The procedure has gained traction in professional sports, where Pittsburgh Steelers wide receiver Hines Ward used it on his sprained right knee to prepare him for the Super Bowl against the Arizona Cardinals in February.
In baseball, Texas All-Star third baseman Michael Young opted for the procedure earlier this month for a left hamstring injury in order to get back on the field soon for the stretch run.
Last October, Dodgers pitcher Takashi Saito had a PRP injection that enabled him to be available for the National League Division Series against the Chicago Cubs. Others who have had the PRP injections include Andrew Miller of the Marlins and Xavier Nady of the Yankees.
Gallagher, who has had tendinitis issues in his knees in the past, is happy to be pitching again this season. He originally figured, at the time of the June injury, that he might be done for the season. He thinks the PRP injection accelerated his return.
Gallagher hadn't allowed a run over three innings in three appearances entering Sunday. He notched his first victory as a Padres pitcher on Saturday, tossing a scoreless 10th inning. He's pitching out of the bullpen this month but figures to get a shot to win a job in the rotation next spring.
That, he said, certainly beats heading to Spring Training coming back from knee surgery, which was an option for Gallagher, though not one he was interested in.
"There was no just letting it heal. The tear was going to be there unless we did something to it to repair it," Gallagher said. "My choices were to play on it and hope that it lasted. It was running the risk of blowing it completely.
"I wanted to do what was going to get me back out there the fastest."
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.