ST. PETERSBURG, Fla. - Even though most everyone who's on the Baltimore Orioles' Opening Day roster returns from last year, there are still plenty of changes from the 2012 opener.

They're both at the top of the order and the bottom.

A year ago, the Orioles hoped that Brian Roberts would return as their leadoff man. Recovering from his second concussion, Roberts returned briefly before succumbing to a hip injury that required surgery.

Healthy again, Roberts is set to bat not in his familiar leadoff spot, but in the ninth hole. In manager Buck Showalter's Opening Day lineup, Roberts is ninth. It will be the first time Roberts bats there since July 31, 2004.

Showalter wants to keep the pressure off Roberts, and in the veteran second baseman's absence last year, found a better choice in Nick Markakis.

While Markakis was in the leadoff spot, Baltimore took off, and he's back there to start the season.

Roberts says he's content with the move, which Showalter discussed with him last week.

"I'm happy to be healthy and playing and my job for the past 13 years had been to be the best leadoff man in the game I could be and now I'll be the best nine-hole hitter I can be," Roberts said.

Showalter said that if Roberts starts hitting well, he'll move up in the order.

In spring training, Showalter had three major injury concerns, Markakis, Roberts and Nolan Reimold. Markakis missed more than three weeks due to a small herniated disc, Reimold had a sore shoulder, and Roberts, who has been limited to 115 games over the last three seasons, was injury-free.

"I feel pretty positive. If you had told me at the end of spring we'd be sitting where we are physically, I'd have signed up for it in blood," Showalter said.

The only Orioles player to suffer a disabling injury this spring was Wilson Betemit, who tore a ligament in his right knee last week. He'll be lost for 6-8 weeks.

Roberts, who is entering the final year of a four-year, $40 million contract, is excited about being introduced to the crowd when the season begins, today in Florida against the Tamp Bay Rays and then Friday at home in Baltimore.

"It's been a long couple of years and I'm just thankful to have the opportunity to go back out there and do it one more time at least. I'll try to soak it all in and enjoy this process," Roberts said.

"You never know what the future has in store so it's a great opportunity to go into the last year of your contract in what could be the last year in a place you spent so long with the opportunity to do something really cool as a team and be a part of it."

In 2012, Jake Arrieta was the Opening Day starter. Jason Hammel was the third starter. For the third straight year, Arrieta is set to start the home opener.

Hammel gets the nod against Tampa Bay's David Price this afternoon.

"It's an honor. Very excited," Hammel said. "Basically what it means, is I get to be the one to get us off on the right foot. I don't take that lightly. Very confident to come out and win there."

It wasn't a surprise that Hammel was named the starter.

"I knew it was a possibility, but I just wanted to take care of what I could take care of and make sure I was going to be healthy so I could even pitch sometime at the beginning of the season," he said. "It worked out and I've kind of mentally preparing for it so it's something I'll cherish and give it our all from Game One."

The Orioles have just two new players on the roster, Rule 5 draft pick, left-hander T.J. McFarland, and utility infielder Alexi Casilla. But as Showalter points out, there are others - Miguel Gonzalez, Manny Machado, Nate McLouth and Steve Pearce - who weren't on the team a year ago at this time.

"We went through a heck of a journey last year. We have a lot of people who know what the journey's about and know what's expected and who they are," Showalter said.

MACHADO SECOND: Machado bats second on Tuesday.

"I like the presentation he gives us initially," Showalter said.

Said Machado: "Buck does everything for a reason. He's trusting me and he has faith."

NEW COACH: The Orioles named Einar Diaz as their seventh major league coach. Diaz, who was slated to be a coach for Bowie, has been with the organization for six years and caught in the majors for 11 seasons. He'll assist hitting coach Jim Presley.