OAKLAND -- The Orioles added a pair of third basemen to the fold, agreeing to terms with second-rounder Jason Esposito and sixth-rounder Nick Delmonico on Monday night, just shy of Tuesday's 12:01 a.m. ET deadline. They also agreed to terms with first-rounder Dylan Bundy.

A third baseman out of Vanderbilt University, Esposito was the 64th overall pick in the June First-Year Player Draft and will receive a $600,000 signing bonus. Known for his defensive skills, the Connecticut native hit .340 with nine homers and 59 RBIs in 65 games this season.

Esposito took to his Twitter page to thank the Vanderbilt program, calling it the "three best years" of his life in Nashville. He also tweeted, "Thank you to all the Baltimore fans for the support! Looking forward to this experience!"

Delmonico, who used his Twitter page to break the story that he was an Oriole, was drafted out of Farragut High School in Knoxville, Tenn. The 19-year-old has a highly advanced bat and has one of the biggest upsides among the Orioles' draftees.

He is listed at 6-foot-3, 215 pounds and hit .426 as a senior with 11 home runs, 45 RBIs and 53 walks. Delmonico won four Class AAA state titles and ended his high school career with 45 home runs, 156 walks and 209 RBIs.

A coveted high school infielder -- believed to be a first- or second-round talent who fell due to money demands and signability concerns -- Delmonico will forgo a commitment to the University of Georgia. His signing brings the Orioles total to 21 of their 50 picks.

Teams had until 12:01 a.m. ET on Tuesday to come to terms with their draftees, meaning official notification has to be in the Commissioner's Office when the clock strikes midnight. A team that does not sign its first- or second-round pick will receive a compensatory pick in the 2012 Draft. That selection will come at the same slot, plus one. In other words, if a team doesn't sign the No. 9 overall pick, it would receive the No. 10 pick -- technically 9A -- the following year. A team does not receive a 2012 pick if it does not come to terms with a selection made with a compensation pick this year.

Prospect Klein to have shoulder surgery

OAKLAND -- Orioles top pitching prospect Dan Klein will undergo exploratory surgery on his right shoulder on Tuesday morning in California, a procedure that will end his season and leaves the young right-hander's timetable for a return uncertain.

Orthopedic surgeon Lewis Yocum will perform the surgery, which will involve repairing the SLAP tear in Klein's labrum that a previous MRI revealed, as well as whatever else needs to done to fix the area. The rehab and recovery will depend on the scope of what's done, which won't be known until Yocum can get in there and see what's going on.

Klein was already doubtful to throw a pitch the rest of the season after an MRI taken in June revealed the SLAP tear, and attempts to rehab the injury ended when he experienced pain while throwing last week.

The 23-year-old went 3-1 with a 1.11 ERA between Double-A Bowie and Class A Frederick this season, but hadn't appeared in a game since June 1. The Orioles' third-round pick in the 2010 First-Year Player Draft out of UCLA, Klein had a history of shoulder problems while with the Bruins, which is one reason why he fell to Baltimore with the 85th overall pick.

Klein helped lead UCLA to two NCAA Regionals (2008 and '10), and the right-hander made 39 appearances in 2010, which tied the Bruins' single-season appearance record and also tied for the Pac-10 lead in appearances with Arizona State's Mitchell Lambson. Serving as UCLA's closer, Klein notched 10 saves in 2010, the second-highest single-season total in program history and the third-most saves among Pac-10 pitchers that year.

Matusz feeling best he has all season

OAKLAND -- Orioles pitcher Brian Matusz acknowledged on Monday that he feels better now than he did at any other point this season.

"It's been a tough year, going through a lot of different scenarios," said Matusz, who missed the first two months of the season with an injury and will start Tuesday against Oakland for his first big league outing since June 30.

"But I definitely feel prepared and feel good about my health physically, and confident going into the start."

The 24-year-old lefty is coming off a shutout in his last start for Triple-A Norfolk, an outing in which Matusz earned rave reviews for improved velocity and the ability to go deep into the game, something he struggled with earlier this season. The win on Thursday raised his record to 2-3 with a 3.46 ERA in nine starts with Norfolk, and the hope is he can continue to build on that progress with Baltimore.

"Brian's a guy that's capable of doing a lot of things well," Orioles manager Buck Showalter said of Matusz, who was projected to be the team's No. 2 starter before a left intercostal muscle strain forced him to the DL. Following Matusz's activation on June 1, he pitched to an 8.77 ERA in six games, prompting the move to Norfolk to get him back to form.

"I just want to see where he is compared to where he was when he left," Showalter added. "[There are a] lot of good things being said about him and he seems to have a good look in his eye and feels good physically. He seems to have a lot of challenges that he had behind him. So, we'll see."