As the Chicago Cubs’ bullpen racks up innings, the heavy workload tests the team’s relievers.

The All-Star break can’t come soon enough for the Chicago Cubs bullpen.

A strength for most of the season, the Cubs’ relievers have been plagued by an injury-marred rotation and short outing stretches. Entering Monday, the Cubs’ 368⅓ relief innings ranked second in the majors, a third of an inning behind the Tampa Bay Rays. No other team had pitched more than 355 innings out of the bullpen.

While the Cubs’ relievers’ 26.1% strikeout rate ranks fifth, their .246 batting average against is fifth-worst and their 1.32 home runs per nine innings is second-worst. The Cubs’ bullpen has a 15.1% home run-per-fly rate. Those high ball-in-play rates can be the difference when a team is involved in as many close games as the Cubs have been this season.

Cubs starters haven’t consistently helped their counterparts in the bullpen. With no deeper starts and a staff restricted to 13 pitchers, the Cubs’ 20% quality starting rate (29th in the majors and 15% below league average) and 4.6 innings per start, tied for last place, put continuous pressure on relievers and allow less room for error.

The Cubs have held a lead in 31 of their 52 losses, including three of four games as they were swept last week at Dodger Stadium.

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“We hadn’t been where we wanted a couple of times from a starter length standpoint, but the bullpen has picked up the slack very well,” manager David Ross said Sunday. “A couple of hiccups here and there, but overall the job has been very, very nice.

“We’ve asked a lot of those guys and (they) understand where everybody is. Some days the guys are hanging in there and dealing with little issues, but continue to take the ball. Really satisfied with the way they have done their job and the way they have competed”.

A day off Monday and a four-day All-Star break next week will provide the bullpen with some much-needed rest. Right-hander Scott Effross’ 39 appearances rank third in the majors, while right-hander Rowan Wick’s 36 starts and 36⅔ innings rank in the top 17 in both categories in the NL.

Veteran right-hander David Robertson had been one of the Cubs’ most consistent pitchers before blowing two saves in the last week. The 37-year-old Robertson has pitched more innings in the first half than the previous three years combined due to Tommy John surgery and his recovery.

“I’m tired of (stinking) out there, so I’m ready to turn it around and get some outs and not allow any more runs,” Robertson told the Tribune in Los Angeles. “We keep playing these tight one-run games with no room for error, and I keep making mistake after mistake and I can’t get the ball into the strike zone. And then when I do, it’s a little too late.”

Robertson doesn’t think his problems are mechanically related. He attributes his recent inconsistency to his way of thinking.

“When I’ve been in the game, if I make a mistake, the game will be tied, so I ended up walking guys and not making enough competitive pitches earlier in the counts,” Robertson explained. “I just have to make better shots at better times and be more efficient. I’m ready for the break to come, and then we can regroup and start again.”

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Ross has often relied on the veteran trio of Robertson, Mychal Givens and Chris Martin in late-inning situations. Givens has been on a roll for the last three weeks. He has not allowed a run in his last nine games (11 innings) with 12 strikeouts and four walks.

Martin was also in a groove between June 17 and July 6, making nine scoreless appearances and recording eight strikeouts with no walks. In two appearances against the Dodgers, he wasn’t as efficient, allowing two runs on four hits, including a home run, though he didn’t walk.

Martin hasn’t walked since May 26. He credits better control and being ahead in the count for putting him in better positions to be aggressive.

Martin, part of the Atlanta Braves’ bullpen during their World Series title run last year, knows what it takes to succeed in the majors in his seventh season. He told the Tribune on Saturday that his right shoulder has been “barking” a bit.

With the workload the Cubs’ bullpen has taken on, a worn relief corps has been challenged lately. Having right-hander Marcus Stroman and left-hander Drew Smyly back over the weekend should help stabilize the rotation and get more innings out of the starters.

“It can be tough when you’re in a situation where you’ve been throwing a lot,” Martin said. “You start to get tired and you start to wear down a little bit, and I’m going through that right now.

“I need to focus mentally and focus on shooting instead of worrying about how my body feels and things like that when I’m on the outside. I’m just trying to get to that All-Star break right now.”