Brandon WorkmanEven the best teams tend to have limitations. The Red Sox’ most glaring weakness stood out Tuesday in Colorado.

John Lackey surrendered three homers while allowing four runs in six innings of work. It wasn’t his best effort, but there’s no need to panic about a couple of missed pitches that landed in the bleachers at Coors Field. Instead, the focus following the Red Sox’ 8-3 loss should be on the seventh-inning bullpen implosion.

Brandon Workman, who hadn’t pitched in a week, was roughed up in his return to the hill. He took over for Drake Britton after Jordan Pacheco led off the bottom of the seventh inning with a double down the left field line and proceeded to stumble his way to recording just one out. Workman was charged with three runs on three hits and a walk, elevating his ERA to 5.05 in the process.

“Not our best night from the mound,” manager John Farrell said. “I thought John made a couple of mistakes that he had to pay for, particularly in a ballpark where if you put the ball in the air, it’s going to carry. The three home runs allowed were not common for him, as strong as he’s pitched for us all year. In that seventh inning, we let that game get away from us with the four runs.”

The first three hitters Workman faced in the seventh inning reached safely. Josh Rutledge, who pinch hit for Rockies starter Tyler Chatwood, singled, and Charlie Blackmon walked before DJ LeMahieu drove in two runs with a base hit into left-center field. That extended Colorado’s lead to 6-1.

The Rockies weren’t done. Blackmon and LeMahieu each moved up a station on an aggressive double steal with Troy Tulowitzki at the dish. Then, after Tulowitzki grounded out to third base for the inning’s first out, Michael Cuddyer dropped a single into right field that plated two more runs.

“We tried to buy him some days of rest. He looked like he hadn’t pitched in a while,” Farrell said of Workman. “The overall command and stuff was down a little bit. The big blow was probably the bloop single by Cuddyer the other way. At that point, the four-run inning spread it out just enough for him.”

Farrell took the ball from Workman following Cuddyer’s two-run single, which gave the Rockies an 8-1 advantage. It simply wasn’t the rookie’s night, and he certainly wasn’t alone in having a bad game. The question, however, is whether this is something that will linger, as Workman is currently navigating uncharted waters.

“It was the first time that he’s gone an additional month throughout the course of his career,” Farrell said of giving Workman some rest recently. “Knowing the number of innings and high-stress innings, we wanted to buy him a little extra time. Like I said, he looked a little rusty out there tonight.”

Workman has impressed the Red Sox this season with both his excellent stuff and his tremendous poise. He’s a virtual lock to make the postseason roster, and he’s expected to play a major role in bridging the gap to closer Koji Uehara. That’s a high expectation for someone in his first year, though, regardless of how impressive he’s been at times.

While the Red Sox’ bullpen has been strong for the most part, the middle innings still represent an interesting dilemma for Farrell. Junichi Tazawa and Craig Breslow figure to be the go-to guys around the seventh and eighth innings, but the rest of the bullpen remains in flux. In other words, it’s not a situation that the Red Sox should be overly confident about with four games left in the regular season.

The Red Sox’ hope has been that Workman would emerge from the pack as a legitimate option for high-leverage situations. At times, he’s looked capable of filling that role, but efforts like Tuesday’s serve as a reminder that it’s no guarantee. And beyond Workman, there are only more questions in terms of piecing together the middle innings. In fact, even Tazawa, who was lights-out at the beginning of the season, hasn’t been quite as overpowering of late.

There’s a lot to like about the Red Sox with October approaching. The offense is extremely productive, the starting pitching looks built for playoff baseball, the bench is as deep as any in the game and Boston has the luxury of a dominant closer. But there’s still that one little area that has the potential to nag the Red Sox.

The Red Sox have some talented arms out in the bullpen, but the relief corps will need to step up in October to ensure that a shaky bridge to Uehara doesn’t become Boston’s fatal flaw.

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