SARASOTA, Fla. -- Orioles lefty Mark Hendrickson isn't just adopting a new delivery this spring, he's also adding a pitch. Hendrickson, a non-roster invitee who is trying to reinvent himself as a sidearmer, has been throwing a slider for the first time in his career.

"To be honest, I'm a completely different pitcher than anybody's ever seen, because I never threw the slider," Hendrickson said. "I always threw the curveball, but down [in the strike zone], you can kind of mess with some grips and see how it comes out -- slower, firmer. [I'll] talk to 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 threw his seventh bullpen session on Thursday since adopting the new approach, and he said his delivery feels very natural despite the short amount of time.

"Obviously there's going to be times I need to kind of incorporate some of the things they're trying, but if you talk to [pitching coach] Rick [Adair], in the first two days I threw in Baltimore, it was exciting to see how quickly I picked up some of the stuff we talked about on Wednesday, and then when I came back and threw on Friday," Hendrickson said. "But the key for me, too, is getting some games where it's just time to compete."

Hendrickson threw to some college hitters over the weekend before reporting to Sarasota and it's possible he might stay at the Spring Training complex when the season starts to continue working on his delivery. Hendrickson could also be assigned to one of the Orioles' affiliates.

"There's probably not a person more excited being here than Mark," manager Buck Showalter said of Hendrickson, who contacted him this winter. "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. You've got to have failure. 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, and we're willing to do what it takes if we think at the end of camp that it's something we want to proceed with.

"I'm not going to say never, but this is a work in progress. You can't just all of a sudden change your arm angle and think you're going to get Major League hitters out consistently."

Ayala trying to decide if he'll pitch in Classic

SARASOTA, Fla. -- Orioles reliever Luis Ayala will decide by Thursday whether to accept an invitation to pitch for Team Mexico in the World Baseball Classic.

"They've said it's my decision," Ayala said of Baltimore's opinion on the matter. "They haven't said [anything]. I'm looking [out] for my future. I talked to the guy from the Mexican team yesterday. I [will] make the decision tonight."

Ayala has not thrown a bullpen session during the first two days of Spring Training, but he's coming off a winter-ball season and is already in game shape.

"My last game was four days ago," Ayala said. "I'm ready. [The Orioles] know me and when they say, 'Yeah, we're going to give you more time.' ... It's good for them to give me some rest. I don't need to throw too much. I could pitch in a game right now."

Center fielder Adam Jones will leave camp for Team USA on March 3, and reliever Pedro Strop (Dominican Republic) will also depart around that time. Strop, who threw a bullpen session on Thursday, will appear in a few of the Orioles' early spring games along with Jones.

"I don't worry about Pete as much with Billy [Castro] there [as pitching coach]," manager Buck Showalter said of the Dominican Republic's team. "I don't think you'll see Pedro overused."

Strop will be participating in his first Classic, and he's coming off his first season with Baltimore, a 2012 campaign in which he went 5-2 with a 2.44 ERA.

"It was a tough decision from the point that I wanted to be here," Strop said of leaving the Orioles' camp. "I just made the decision to go out there and represent my country. You don't see that very often. You see that only every four years, and you don't know where you are going to be in four years, so that was the point that made me decide to go over and pitch."

Strop struggled down the stretch last season, posting a 5.12 ERA in his final 25 appearances, but he didn't think his performance was related to fatigue and isn't worried about the Classic having any negative effects on the 162-game baseball season.

"I think it was just a bump in the road, and that's already in the past," Strop said. "I am just going to come right out and do whatever I can to help the team.

"[Castro] knows he has got to keep me fresh for the season, because that's the most important thing, is this year. You are always proud representing your country, but the important thing is the year."