Why Patton Can't Be Lefty Specialist - HUH?

Troy Patton continues to be effective in spring training.  He pitched one inning yesterday, pitching around a walk and a hit batter to notch his sixth outing without a run scoring. 

In other news in Orioles camp yesterday, they reported they has signed Dontrell Willis to a minor league deal.  Jim Henneman proposed they look at making Willis a lefty specialist.  In his argument, he made this statement:

The Orioles don't have such a (lefty) specialist, because Troy Patton is as effective against right-handed hitters as he is against lefties

I don't think I understand his case there but it my simple way of thinking a pitcher who can get batters out from both sides of the plate is better than one who can only get batters out on one side of the plate.