Tillman rewarded the Orioles' patience by winning 16 games and becoming an All-Star.
''He graduated to another level last year,'' manager Buck Showalter said.
In one of the best trades in team history, Baltimore acquired Tillman, Adam Jones and George Sherrill from the Seattle Mariners for pitcher Erik Bedard in February 2008. For three years, Tillman bounced between the majors and minors before breaking out in late 2012.
Tillman went 9-3 with a 2.92 ERA in 15 games in 2012. Last year, he was 16-7 with a 3.71 ERA, and the Orioles think he can improve even more.
''There's another level he can go to,'' Showalter said.
In his first three seasons with the Orioles, Tillman was 7-15 with an ERA well over five in each year.
The 25-year-old Tillman hopes to be the Opening Day starter on March 31 when Baltimore hosts the Boston Red Sox.
''I think it would be a big honor. I think it's a big deal,'' Tillman said.
Showalter won't name his first starter for a few weeks, but it is obvious that Tillman will be the man. He tries to avoid being presumptuous about being the staff leader.
''We've got five No. 1s. We're only as good as the starter that day,'' Tillman said.
Besides Tillman, the Orioles have Wei-Yin Chen, Miguel Gonzalez and Bud Norris in the rotation. The fifth starter isn't set.
''We've got a lot more than five guys capable of making the starting rotation this year. That's a good thing,'' Tillman said. ''It creates competition. You thrive off that. Competition gets you going. I'm excited for the season.''
Tillman, a Mariners' second-round draft choice in 2006, came to Baltimore with great promise. Since his debut in 2009, he has had five pitching coaches. Dave Wallace was hired to that position in October.
Wallace has promised not to tinker with his new staff unnecessarily. He has watched Tillman work out a few times, and Showalter knows Wallace likes what he sees.
Tillman doesn't yet consider himself a finished product.
''For me, personally I look at it as it's a process. It's one step. You've always got to be working in this game. It's a humbling game,'' Tillman said. ''I don't want to be complacent. I don't want to think you have it figured out, but you don't. You've got to find a way to improve.''
Showalter is confident Tillman will continue to work to get better.
''The things you see with Chris that you didn't see two or three years ago, the confidence of him asking a question in a drill,'' Showalter said. ''He's going to be somebody that teammates want to please.''
NOTES: The Orioles claimed OF Jimmy Paredes on waivers from Miami. Paredes, who played parts of the last three seasons with Houston, has a .234 average in 118 major league games. . RHP Alfredo Aceves and C Johnny Monell haven't reported to camp. . RHP Suk-min Yoon visited camp with his agent, but declined to speak about his contract. The Orioles have yet to officially announce an agreement with the 27-year-old South Korean.