LAKELAND, Fla. (AP) -- Jacob Turner pitched 12 2-3 innings in the major leagues last year -- enough to realize he still had a lot to work on.
"Hitters at the big league level are going to really show what your weaknesses are," the Detroit right-hander said. "They're going to make your weaknesses kind of compound on top of each other."
Expectations are high for the 20-year-old Turner, who was drafted in the first round by the Tigers in 2009. Detroit hasn't settled on a No. 5 starter, and Turner is one of several pitchers in the running during spring training. That competition figures to be one of the most interesting subplots for the Tigers as they prepare to defend their AL Central title.
Detroit appears content to fill its final rotation spot from within. General manager Dave Dombrowski shed some light on the team's thought process a couple weeks ago when he rattled off a list of possible candidates, including Turner, Drew Smyly, Andy Oliver, Casey Crosby, Duane Below and Adam Wilk.
Baseball America ranks Turner as Detroit's top prospect, and he was certainly solid last year at Double-A Erie and Triple-A Toledo. He made three starts as a Tiger, posting an 8.53 ERA, so he still has to show he can handle a full-time role in the majors.
"The biggest thing I think with Jacob is getting comfortable throwing his changeup," pitching coach Jeff Jones said. "His changeup has looked good on the side. We want him to be able to carry that into the game and command his stuff.
Oliver was drafted the same year as Turner, one round later. He's also made an occasional start with the Tigers, going 0-5 with a 7.11 ERA over the last two seasons. Oliver struck out 143 batters in 147 innings at Toledo last year, but he also allowed 149 hits and 80 walks for the Mud Hens.
Smyly is a bit of a wild card. He was drafted in the second round in 2010 and breezed through last season, going 7-3 with Class A Lakeland and then 4-3 with a 1.18 ERA at Erie. The left-hander has been so impressive he's being mentioned as a candidate for a rotation spot despite not being a member of Detroit's 40-man roster.
"There's a lot of people competing for it, so you can't really think about it," Smyly said. "It's awesome to know you're in the running."
Like Smyly, the 23-year-old Crosby has yet to pitch in the big leagues. He spent much of the 2008 season recovering from reconstructive elbow surgery, and the southpaw's left elbow gave him problems in 2010, too.
Crosby was able to make 25 starts at Erie last year, a step in the right direction. He struck out 121 in 131 2-3 innings.
The 26-year-old Below -- another left-hander -- is the candidate who pitched the most for the Tigers last year, making 14 appearances, including two starts. He had a 4.34 ERA in 29 innings with Detroit, and also pitched impressively for Toledo, going 9-4 with a 3.13 ERA -- exclusively as a starter.
Wilk, an 11th-round pick in 2009, showed impressive control at Toledo last season, walking only 14 hitters in 102 2-3 innings. He made five appearances with the Tigers, all in relief.
Detroit doesn't start exhibition games until next month, and that's when these pitchers will really be on the spot. Until then, they'll have a chance to settle in and work alongside established big leaguers like Justin Verlander, last year's Cy Young Award and MVP winner in the American League.
"It's a good idea to watch other hitters and other pitchers on your own staff, to get an idea of what they do, but you have to be careful that you don't try to emulate them exactly, because your stuff might not be the same," manager Jim Leyland said. "Your method of getting somebody out might have to be different than somebody else's. There's not many Justin Verlanders, so you have to figure out what works for you."