Tillman has yet to pitch in more than 86 innings in any of his four stints in the majors. From 2009 to 2011, he had an ERA of at least 5.40 while receiving about a dozen starts each season. He was slightly below average in 2009 and 2010, though he did turn things around somewhat in 2011. His 5.52 ERA in 62 innings made it difficult to tell, but Tillman struck out more batters than he had before, limited his walks at least from the previous season, and stopped giving up a ton of home runs. But he had an unlucky BABIP of .348 -- an almost .100 point increase from 2010 -- which, along with his improvements listed above, explains why his FIP (3.99) and xFIP (4.83) were the lowest of his career at that point.
Fueled by a disappointing final start in August 2011 and not being a September call-up, Tillman trained with Brady Anderson in the winter. In the spring of 2012, he spent the first portion of the season in Norfolk, but he also got to work with Rick Peterson, who was hired as the organization's director of pitching development last January. And, as you're likely aware, Peterson changed some things:
The Orioles put all their pitchers through biomechanical testing last spring, a product of new director of pitching development Rick Peterson, and Tillman's results coincided with what [pitching coach Rick] Adair originally wanted to do. And so the overhaul began with an emphasis on adding movement, with a stronger Tillman able to generate increased power, diligently working on drills when he opened the season with Norfolk, and ramping up efforts when Peterson made his rounds around Triple-A a few weeks later.Tillman, with a stronger frame and a tweaked pitching motion, put up his best numbers at Norfolk since 2009. Take a look:
2009: 96.2 IP, 2.70 ERA, 2.76 FIP, 9.22 K/9, 2.42 BB/9
2012: 89.1 IP, 3.63 ERA, 2.98 FIP, 9.27 K/9, 3.02 BB/9
They weren't quite as good, but they were still more than solid. But unlike in 2009, Tillman was ready when he was promoted this time. In his season debut on July 4 in Seattle, he pitched 8.1 innings of two-hit ball and only surrendered two unearned runs. In his next start, Tillman failed to make it out of the first inning, allowing seven runs (one earned) in a frustrating effort. But he bounced back, and he kept plugging along while making 15 starts and pitching 86 innings for a playoff-bound team. He finished with his best numbers to date: 2.93 ERA, 6.91 K/9, 2.51 BB/9. He was pretty fortunate on batted balls (.221 BABIP), which his 4.25 FIP and 4.34 xFIP reflect, but the strikeout and walk rates were the best of his career. Tillman's probably not a sub-3 ERA pitcher, but something around 4 or maybe a little above isn't unreasonable to expect.
It's also a strong sign that Tillman threw the ball the hardest since his rookie season. Here are Tillman's fastball velocities in each of his pro seasons, per Pitch F/X data:
It's probably not a coincidence that Tillman had a velocity increase after training hard in the offseason and getting tutelage from Peterson, but it's possible. Eighty-six innings is far from a large sample size. And just because Tillman was a pleasant surprise in 2012 doesn't mean he's guaranteed anything in 2013 if he reverts back to his 2009 or 2010 self. The Orioles will have several other starting pitchers waiting at Norfolk, chomping at the bit for a chance to prove themselves. He'll have to keep putting in the work, and he'll need to both stay healthy and pitch well in order to eventually surpass the 100-inning barrier. But it seems like Tillman knows that, especially if you believe Norfolk pitching coach Mike Griffin (per Brittany Ghiroli's link above): "If his fastball command at Norfolk wasn't as good as he wanted it, he was really upset. And then his side day was a major, major man on a mission."
That's the kind of effort it's going to take for Tillman to replicate his recent success. And while the Orioles do have some other options if he falters, they'd much rather have Tillman keep pitching like the guy most fans thought they acquired from the Mariners for Erik Bedard.