So can we now raise the worry flag on Nate Robertson?

He had already struggled in his previous two outings, and hadn't made it to the sixth inning in his last five starts.  And last Wednesday in Tampa Bay, Robertson "tweaked" his back, but insisted it wasn't the reason for his struggles.  

Yet he has to be hurt, right?  An injury seems like the only plausible explanation for Robertson going from arguably Detroit's second-best starting pitcher in the first month of the season to a guy who can barely notch the amount of innings required for a win.  

In April, his record could be attributed to not getting much help from the batting order and bullpen.  But the rest of his numbers said he was throwing well.  Since then, however, he hasn't been fooling anyone.  And last night, he was a mess.  The Rangers got four hits and two walks without making a single out.  And they weren't just poking the ball between fielders, either.  

Robertson had some trouble locating his pitches, especially inside to right-handers.  You could say he was getting squeezed on a few of those calls (which Pudge seemed to indicate to home plate umpire Jerry Crawford), but his pitches also weren't moving very much.  Jim Leyland thought Robertson's velocity was down, but eventually admitted he can't figure out what's going on.  

So what can the Tigers do?  It seems like Leyland needs to call Robertson into his office, close the door, and ask his pitcher to be straight with him about his health.  But if Robertson insists he's fine, maybe the coaching staff has to take that decision out of his hands.

Chuck Hernandez has already helped Robertson adjust his mechanics a bit, but does he need to look even closer?  (Surely, he already has been.)  Does Robertson need to be taken out of rotation and work out whatever issues he might be having in the bullpen?  Leyland seemed to hint at that possibility.  He certainly has a few candidates to take that spot (especially if Kenny Rogers is looking ready to come back, pending a doctor's consult and a few rehab starts).  

On the bright side, the Tigers' bullpen pitched very well and gave the team a chance to come back.  Jason Grilli, in particular, was impressive in his four innings, giving up no runs and striking out five batters.  Was that a bid for a spot start?  Consider yourself on notice, Nate.  Cutting more hair off probably isn't the answer.