The Orioles, especially manager Buck Showalter, believe he can.
The 6-foot-9 left-hander — a veteran of five different major league teams, including a stint with the Orioles from 2009-2011 — didn't pitch professionally last season. No teams were interested in his services. His phone was not called. So instead he pitched in a semi-pro league in York, Pa., the same way he first laid a path to the big leagues.
In December, Hendrickson decided to try a suggestion Showalter gave him two years ago: lower your arm slot to increase the deception in your arms-and-legs delivery.
He called Showalter and told him, and during the Orioles' minicamp last month, he showed the team his new sidearm delivery. It earned him a minor-league contract and an invite to spring training. On Thursday, he threw sidearm off a mound for just the seventh time. It has caught on. Hendrickson has turned his curveball into a slider that comes out with strong movement from his arm new angle. He said throwing overhand now seems foreign to him.
"To be honest, I'm a completely different pitcher than anybody's ever seen," Hendrickson said. "Down there, you can kind of mess with some grips and see how it comes out. Slower, firmer. [I've talked] to [fellow sidearmer] Darren [O'Day] and see how he throws stuff down there. I like what I got for feedback as far as the spin today with the couple that I did throw, so that was good."
Hendrickson, who has mostly pitched in relief in the big leagues since 2010, is still a long shot to make the team out of spring training. His new delivery is a work in progress, and Showalter said Hendrickson could continue to lower his arm angle with the help of pitching coach Rick Adair, who has a reputation for working with unconventional arm slots.
He could remain in extended spring training to continue refining the delivery, or he could be assigned to one of the team's minor league affiliates. Hendrickson said he's open to working his way back. Most important to him is the opportunity.
"There's probably not a person more excited [about] being here than Mark," Showalter said. "It's not that he missed it, but you can tell that he enjoys it. It's like he's got a new toy. It's kind of like R.A. Dickey."
While with the Texas Rangers, Showalter was instrumental in convincing Dickey to try his hand as a knuckleballer and, at age 38, Dickey won last year's National League Cy Young Award.
This offseason, Hendrickson realized his old way of pitching wasn't working. He posted a 4.80 ERA in his previous stint with the Orioles and a 5.03 career mark. His big league career seemed over, unless he chose to adapt.
"You've got to have failure," Showalter added. "It's got to be, 'I can no longer do it.' He knew after a year away that it was over, conventionally the way he was doing it, but he knows that this isn't a one- or two-week tryout. This is something that takes time, and he's willing to do whatever it takes."
Hendrickson appears dedicated to the change. Before reporting to Florida, he pitched to college batters and sought feedback on his delivery.
"I just threw to some hitters just to get some feedback. Just to ask, 'Hey, what are you seeing, what is the deception? What does it look like?'" Hendrickson said. "I got some feedback from some lefties and obviously some righties, as well. That's important just to have me take it all in and learn."
Hendrickson said the new delivery also has alleviated stress on his arm.
"It's a lot easier," he said. "There were times where it would take me a little while to get loose. It's just a different angle, and there's different soreness that I'm going through, but I think it's a lot easier. It's just more fluid, I would say, especially in the first five minutes of throwing. [I] remember Cla Meredith when he was with us, and just watching him in the bullpen, how quickly he got loose. And that's just what I've experienced, too. It's like, 'Wow, the first couple throws, it just seems a little freer.'"
Showalter points to the fact that Hendrickson is a solid athlete — he played parts of four seasons in the NBA before his baseball career — and a quick learner.
And the manager is intrigued about what Hendrickson's comeback could become.
"When he gets it right, he's going to be throwing it from the second baseman," Showalter said. "He's going to be able to create quite a unique angle."