The second-year right-hander is one of several candidates hoping to nail down one of the two open spots in the Rays' rotation. Competing against him are Edwin Jackson, J.P. Howell, Jason Hammel, Jeff Niemann and Mitch Talbot.
"I think the competition will force me to do better," Sonnanstine said. "The competition is going to be very heavy.
"We've got a lot of nice young arms right now, so I'm just going to try and do my best this spring, and hopefully it will all work out."
The numbers from Sonnanstine's initial campaign with the Rays in 2007 are deceiving. He went 6-10 with a 5.85 ERA in 22 starts, but keep in mind, he went 1-8 in his first 13 starts. He then went 5-2 in his last nine starts and won three straight games in the process, dispatching, in order, the A's, Yankees and Orioles, while pitching to a 2.37 ERA.
Sonnanstine said he picked up experience and built his confidence through his 2007 experiece.
"Now I can take that mound and know I'm going to do well," Sonnanstine said. "Just logging those innings and learning as much as I could, putting it all together in the big equation, really helped me."
A big part for any rising Major Leaguer is acquiring a sense of belonging and Sonnanstine was no different.
"Right when I first got up, I had two good starts and felt like I belonged," Sonnanstine said. "After that, I ran into quite a few losses, and that shook my confidence a little bit. By the end of the year, I'm picking [Dan] Wheeler's head, talking to [Jay] Witasick. That helped. Logging the innings, talking to the older guys, and the experience, that really helped."
By reaching the big leagues, Sonnanstine achieved a lifetime goal.
"I'd worked toward that goal every single year since I was a little kid," he said. "So now that I've reached that goal, I need to set new ones that are harder to reach."
Hinske fondly recalls Red Sox fans: Eric Hinske is in camp as a non-roster invitee for the Rays this spring after hitting just .204 for the Red Sox in 2007. Despite the subpar season, the veteran said the Boston fans never got on him.
"No, they actually liked me," Hinske said. "I made a couple of good plays in the outfield, and I knocked over a catcher once. You play hard there, the Boston fans appreciate you."
Hinske said he had a lot of fun playing for a championship team.
"Yeah, it was a lot of fun," Hinske said. "It was fun to see 25 guys not really caring about themselves or their numbers, just wanting to win ballgames. It was very cool. It was definitely an experience winning a World Series."
Don't worry: Rays manager Joe Maddon is not worried about Rocco Baldelli being timid or going at game speed while returning from the 2007 season, which saw Baldelli miss most of the season with hamstring problems.
"Whenever you have an injury as an athlete, there's always that mental adhesion in the back of your mind, and it kind of does restrict you to a certain point," Maddon said. "So with him, we want to ease him in when he gets to that area [mental adhesion] and then beyond it. It's going to take some time to really get it to where we want it to be. ... The object is to get him ready by the opening game of the season, whatever that takes."
Baldelli is not scheduled to play in the outfield until late next week.
This and that: Dioner Navarro will not catch until Monday's game against the Tigers. Maddon explained he decided to hold back Navarro a little, because he started later due to the time he spent with his ailing mother in Venezuela before reporting late to Spring Training. ... The Rays have arranged to use the designated hitter in Friday's game against the Reds and Sunday's against the Pirates. Both games will be in National League parks, which would normally mean no use of the DH. ... Thursday's workout was the final Spring Training workout for the Rays at the Raymond A. Naimoli Complex. Next season, the Rays will hold camp in Port Charlotte, Fla.
Up next: The Rays travel to Sarasota on Friday to play the Reds in a 1:05 p.m. ET contest at Ed Smith Stadium. Jackson will start for the Rays and will be followed by Hammel, Sonnanstine, Grant Balfour, Chad Orvella and James Houser; Homer Bailey will start for the Reds.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.