While Brandon Inge and Omar Infante are getting lots of credit for being pleasant surprises, and Carlos Guillen and Pudge have received accolades for exceeding expectations, Nate Robertson may be the biggest surprise of all. With the exception of two bad outings against Anaheim, Nate has been a very solid performer-especially for a guy that was even in the rotation at the start of the year.

I’ve talked before about defense independent pitching, which looks at the stats that a pitcher has direct control over (strike outs, walks, and home runs). Early in the season Robertson was striking out better than a batter an inning. He’s slipped in that regard, but he’s also allowing fewer walks and fewer home runs. Even still, he is exceeding his fielding indepent pitching ERA which in the past I’ve attributed to luck. His actual ERA is 3.81 and his FIP ERA is 4.09. In Nate’s case the difference comes down to pop-outs.

The folks at Hardball Times have been tracking the types of hits that pitchers have allowed. The types of balls in play that a pitcher allows have an impact on the fieldability of balls. This table shows the league averages for the different types of balls in play (for the full article click here):

Type             Percent     Out%       HR%
Groundballs        45%        72%        0%
OF Flyballs        30%        75%       12%
Line Drives        19%        26%        2%
IF Flyballs         6%        97%        0%

Not surprisingly, line drives are most likely to be hits, and infield flys are most likely to be outs. Now let’s take a look at Nate Robertson’s hits allowed and the league averages (here’s a link to all the stats)

           ERA    FIP    DER   LD%   G/F  IF/Fly   K/9  BB/9  HR/9   
AL League  4.50   4.50   .691  .178  1.20   .159   6.3   3.4   1.1  
Robertson  3.81   4.09   .750  .156  1.36   .356   7.9   3.7   0.9

Nate has had much better defense behind him than the league average (DER is defense efficiency ratio and it represents the percentage of balls in play that are turned into outs). But the reason has the defense had been better at generating outs is that Nate isn’t allowing a lot of line drives, and because more than a third of the fly balls he allows never leave the infield. Nate’s ability to induce fieldable balls, combined with his defense independent performance have helped provide Nate with the 14th best ERA in the AL.

Other Notes:
-Maybe Dmitri’s home run last night will help settle him down a little bit. Young has always been an agressive hitter, but he’s swinging at just about everything that they’re throwing to him. Last night he saw 14 pitches in 6 at-bats, and he swung at 10 of them. In Sunday’s game, if you take out the intentional walk, he swung at 14 of the 19 pitches thrown to him.

-Franklyn German’s failure last night will make it harder for Detroit to let go of Urbina. While I think German got squeezed on the walk to Blake, he had no control when he allowed the homer to Broussard.

-Tom Gage reported today that Fernando Vina isn’t close to returning which means Infante will get to continue and establish himself as part of the next Tiger’s core. He managed to reach base twice leading off last night, but he also looked bad striking out his first to trips up and swinging at the first pitch late in the game with Monroe on second.