When CC Sabathia is on, we know what he is capable of.  The Yankees were on a five-game losing streak heading into their series with Boston and needed Sabathia badly.  They needed the lefthander to deliver a masterful performance.  One that would right the ship back into the sea of victories.  And Sabathia delivered.  7.1 innings pitched.  10 strikeouts.  Just one earned run.  High velocity.  Excellent movement of pitches.  Control and command and swagger.  Fastball, slider and changeup in the right spots.  That is an ace.  And the Yanks need their ace right now more than ever.

No one should question Sabathia since 2007 (115 wins).  What a throwback.  An innings eater, a guy who carried the Indians, Brewers and Yankees from 2007-09, respectively.  But this is a different Sabathia.  CC is older, the velocity comes and goes.  He had a bone spur removed in the offseason.  He often gets hit early and has to battle through games, and it isn't pretty to watch even if he saves the bullpen for the team.

If CC is on, life is far different for the men in pinstripes.  If he is off and not locating and struggling in the beginning of games and not being an ace, even an ace with lower velocity who has to use his pitching creativity, the Yanks are in trouble.

To be CC or not CC.  The Yanks hope the former always holds true.  Because if it does, October awaits.

By:  Mike Lindsley, "Mid-Day with Mike," 1-4, Yankees pre/post game host on 104.5 The Team ESPN Radio.  Follow him on Twitter @MikeLSports.