By Bruce Levine–

CHICAGO (CBS) — The Cubs are off to a great start, and despite losing 8-1 to the Pirates on Wednesday evening, they are playing solid baseball. Perhaps the biggest concern to date centers around a lack of innings pitched by the starting rotation.

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Chicago right-hander Kyle Hendricks has been the poster child for not going deeper into games. An elevated pitch count has been his undoing so far. As a prime example, Hendricks pitched five innings and 96 pitches Wednesday and left the game trailing 2-1. He allowed five hits and three walks — including one with the bases loaded in the fifth inning — while striking out six. What was startling about this outing was that Hendricks, who relies heavily on his pinpoint control, had walked only one batter in his three previous starts.

Collectively, the Cubs’ five-man rotation has created extra stress on an already overused bullpen. The average innings per start for the Cubs rotation through 20 games is 5.76. That failure to get into the sixth and seventh innings has left a lot of work for the bullpen to handle.

In 2014, Hendricks averaged 6.1 innings per start, going 7-2 in 13 games. A case can be made for cold weather impacting all pitchers in the Midwest and on the East Coast early in the baseball season, but most pitchers discount that theory, believing they are the only ones moving consistently in a game, keeping them warmer.

To his credit, Hendricks admitted he hasn’t been good enough. He’s 0-1 with a 5.23 ERA and 1.21 WHIP. Chicago is 2-2 in his four starts.

“I am always a slower starter,” he said. “This one has been particularly slow. All four starts have not been great. I have not been able to get deep into a ballgame. It is not crisis of faith, but it is one of those points where your confidence has to change a little bit. You just have to trust your stuff.”

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The Cubs bullpen has had two injuries to deal with in the early going. Justin Grimm and Neil Ramirez both went on the disabled list within days of each other.

Grimm was a workhorse in 2014, pitching in 73 games after being converted from starting. Also a converted starter, Ramirez was a primary setup man who logged 50 appearances and a trip to the DL last year.

Burning out young, valuable power arms is something this Cubs management group is wary of.

Manager Joe Maddon has had to juggle the bullpen in order to keep it fresh. Four of his relievers have appeared in at least half of the team’s 20 games. Brian Schlitter was overexposed before he was sent back to the minors last weekend.

“From what I have seen, we can play with anybody I’ve seen so far,” Maddon said. “We have to pitch (better  in the middle. That is one area we have to get a little stingier with. Overall, the later part of the bullpen has been real good.”

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Bruce Levine covers the Cubs and White Sox for 670 The Score and CBSChicago.com. Follow him on Twitter @MLBBruceLevine.