There is a danger to allowing one-run games to play too substantial a role in coloring the judgment of a team. When the Red Sox were amidst an 11-game winning streak just a few weeks ago – a run that included improbable come-from-behind, one-run wins – the team’s lineup depth was heralded. Now, after back-to-back one-run losses on the West Coast swing, it would be natural to look at the team’s failure with runners on base and to conclude that the lineup is lacking.

Certainly, the Sox did not appear destined to suffer a 5-4 loss to the Mariners on Friday. They jumped on 30-year-old rookie starter Chris Jakubauskas for four runs in the first three innings. But just as was the case against Angels 30-year-old rookie Matt Palmer on Wednesday, the Sox could not sustain the pressure.

Instead, the team mustered just two hits and no runs over the final six innings. For the fourth straight game of this six-game roadtrip, the Sox went through a period of several innings in which their lineup appeared utterly feeble. Compounding the issue, the team is not capitalizing on those opportunities that it has seen over the past couple of days, going 5-for-32 with runners in scoring position on Thursday and Friday.

The result has been a three-game losing streak, and the Sox’ second worst stretch of the season. The worst? Well, that would be on the team’s season-opening run of traveling chaos, when the team pinballed from Fort Myers to New York to Boston to Anaheim to Oakland.

Perhaps it’s mere coincidence that, on the field, the Sox have been playing as if jet-lagged again on their second West Coast trip. Even so, it seems safe to say that the team is looking forward to the conclusion of this weekend, which will mark the end of travel during this regular season to the Pacific time zone.

Here are five other things we learned on Friday:

THE LONGBALL REMAINS JON LESTER’S NEMESIS

The pure stuff remains that of a dominant pitcher. Jon Lester still has the mid-90s fastball, the devastating curve and one of the most feared cutters in the game. But the execution and results simply are not what they were a year ago, something that is clearly preying on the 25-year-old pitcher.

On Friday, the Sox entrusted him with a 4-0 lead after three innings. In 2008, such a stake was a near-guarantee of victory. Not so this year.

Lester gave the Mariners five runs in his 5.2 innings of work, his record falling to 2-4 with a 6.51 ERA. A mental lapse proved huge in that unraveling.

With the Sox up 4-1, Lester’s failure to convert a comebacker into an inning-ending double play (he was confused when he did not see Julio Lugo covering second, even though second baseman Dustin Pedroia was in position to receive the throw) kept the inning alive. In the next two batters, the Mariners plated four runs, first on a two-run single by Franklin Gutierrez, then on a two-run homer by Ichiro Suzuki.

While the mental lapse was glaring, it should not obscure the fact that Lester is permitting homers at a startling rate. With Ichiro Suzuki having taken him deep twice on Friday, Lester has now allowed 10 homers this year, tied for most in the American League and second most in the majors. A year ago, he allowed just 14 homers in 210 innings.

“I'm just not throwing the ball well,” Lester told reporters. “Just terrible outings and terrible execution of pitches.”

The fact that Lester is striking out batters at a career-high rate, that his walk totals remain almost identical to what they were a year ago, and that his stuff remains impressive suggests that he has the working components for a major turnaround. But it would also appear that, judging by opponents’ hearty hacks against him, he is missing in the strike zone by leaving the ball over the middle of the plate, and opponents are capitalizing.

What is even more apparent is that Lester will not become complacent about his struggles. Even with the security of a five-year contract extension, the pitcher insists that his frustration will yield both work and eventually results.

"I'm busting my (expletive) to perform every five days, and I'm not performing," Lester told reporters. "There will not be a pitcher for the remainder of the season that will work as hard as I will to get to where I was last year…It's little things that are screwing up my outings, and it will turn around.”

IT WILL LIKELY BE A WHILE BEFORE WE SEE DAVID ORTIZ

The markers of David Ortiz’ struggles are now glaring. He is hitting .208 with a .618 OPS. He has gone 144 at-bats without a homer, the second-longest of his career, behind only a 145 at-bat rut that ran from 1998-2000, and included a full year in the minors. On Thursday, he went 0-for-7 and stranded a dozen runners, and his message on his way out of Anaheim was simple: “Papi stinks.”

Those obvious frustrations made it apparent to the Sox that they needed to give the slugger a day off, and perhaps more. In the Red Sox Pre-Game Show, manager Terry Francona indicated that Ortiz might remain out of the starting lineup for the rest of the weekend (something that the Boston Herald is reporting the Red Sox have decided to carry out), with the Mariners scheduled to start a pair of left-handed pitchers on Saturday and Sunday.

“He needs (time off),” Francona said on the Pre-Game Show. “Maybe it was my mistake in waiting this long. I hope I didn’t wait too long. Definitely today, maybe tomorrow. For his good, which ends up being for our good, we’ve got to let him take a breather. It was eating him alive yesterday. We could see it. Sometimes, you just have to let a guy step back.

"I don’t know (that it will be just one day)," Francona added. "They’ve got two lefties coming up...We’ll get this thing figured out."

OPPONENTS ARE NONE TOO KEEN ON PITCHING TO JASON BAY

In back-to-back games, Jason Bay has nearly deposited a game-winning homer into the left-field stands in the late innings. On Thursday, his deep fly in the ninth inning died on the warning track. On Friday, he again hit a ball that might have been out of another park. Instead, the ninth-inning shot once again died on the warning track against the Mariners.

With Ortiz on the bench while looking for his power stroke and Kevin Youkilis still on the disabled list with his strained oblique, Bay is the lone legitimate power threat in the Sox lineup. Opponents will no doubt react accordingly.

On Friday, Bay walked three times against the Mariners. He is currently on pace to walk 140 times this year. Until Ortiz and Youkilis can both return to the lineup and demonstrate that they are ready to produce, it seems unlikely that such a walk rate will slow down.

Along those lines, it will be particularly interesting to note what happens with Bay in the lineup when Youkilis does return from the D.L. Though the Sox could revert to having Bay hit sixth, his production has been so exceptional, and Ortiz’ so limited, that it would surprise no one if Bay continues to occupy the third or fourth spot, with Ortiz moving down.

THE RED SOX ROTATION WILL SOON LOOK DIFFERENT

With Lester’s struggle, the Sox rotation now has a 5.96 ERA, worst in the American League and second worst in the majors. That number and status is vastly out of line with the expectations that accompanied the group into the season, and is clearly unacceptable for an aspiring playoff team.

Change is now inevitable, both in the near-term and again later. Daisuke Matsuzaka made his third and most impressive rehab start for Triple-A Pawtucket, pitching five innings and giving up two runs on just three hits while striking out nine and walking one. He would appear to be ready to reclaim his rotation spot from Justin Masterson during the coming Red Sox homestand.

John Smoltz, meanwhile, threw two innings of an extended spring training game in what was described as the sort of impressive outing for which the club was hoping when it shut down the 42-year-old to focus on strengthening his shoulder. He will pitch three innings in extended spring training on Wednesday before the club determines the next step of his rehab assignment.

THE PITCHING STAFF ISN’T THAT FAR REMOVED FROM BEING AMONG THE BEST

Lester left seven outs for the Sox bullpen, and once again, Boston’s relievers proved capable of recording them without allowing a run. Daniel Bard worked 1.1 scoreless innings in the first one-run game in which he’d seen action as a major leaguer. Takashi Saito then followed by working a scoreless eighth.

The Sox bullpen now has a 3.06 ERA on the year, second best in the majors. That number is all the more impressive given that the bullpen is recording, on average, 10 outs a night.

If the Sox’ starting rotation corrects course, then Boston has now shown over the first 5+ weeks of the season that it has the components of its deepest bullpen under Terry Francona.