The Red Sox said all spring that their best lineup features Jacoby Ellsbury as a leadoff hitter. Monday might be a good time for them to start testing that hypothesis again.

If Sox manager Terry Francona decides to go that route, there would be a notable symmetry to taking that course. On May 31, 2009, the Sox dropped Ellsbury from first to ninth in the batting order against the Blue Jays and starter Ricky Romero – the same pitcher who will take the mound for Toronto on Patriots’ Day at Fenway Park.

Certainly, Ellsbury looks like a player who is putting together the sort of at-bats that would make him a presence in a leadoff spot that he has long embraced. On Sunday, with the Red Sox and Blue Jays tied, 1-1, in the bottom of the second, Ellsbury jumped on a 2-0 fastball down the middle and blasted it more than 400 feet down the right-field line for a three-run homer, a game-changing blow in Boston’s 8-1 win. (Recap.)

“Sitting on a pitch I could drive, 2-0, that was one I could do something with,” said Ellsbury.

It was a no-doubt shot and also a reminder that Ellsbury, beyond being one of the fastest players in the game, has intriguing power potential that had him appearing poised for a breakout in 2010 (before his rib injuries sabotaged the year) and again this spring.

After the game, there was also the evidence of Ellsbury’s unshakable confidence. Even while fielding question after question about his brutal 2010 season, he has remained steadfast in his faith in his abilities, a notion that came to the fore when the center fielder was asked if his shot down the right field line was as far as he could hit a ball.

“I’ve still got a little bit more in me,” Ellsbury joked.

Ellsbury is the one player on the Sox who truly relishes hitting leadoff, who considers it part of his identity as a player. If he struggles from the top spot in the order, the 27-year-old will view it as a function of his dealing with a rough stretch at the plate, rather than where he is hitting.

That said, one shouldn’t get carried away with a single swing. It was Ellsbury’s only hit of the day, as he ended up going 1-for-4 with that homer and a strikeout. His .196 average, .288 OBP, .413 slugging mark and .701 OPS hardly scream top-of-the-order hitter.

Nor should one get carried away by the fact that Ellsbury leads the Sox in homers (3) and is tied for the team lead in RBI (8). After all, he’s enjoyed early power bursts before, hitting three homers in his first 19 games (67 plate appearances) in 2008. He then went on to hit just six homers in his remaining 542 plate appearances.

Still, he’s looked like a hitter with a plan at the plate. In contrast to the road trip that opened the season when he was perhaps overly aggressive at times (especially in Cleveland), Ellsbury has appeared to be looking for specific pitches in specific spots, rather than swinging liberally.

If the Sox believe that Ellsbury is their best long-term answer at the top of the order, then there would appear to be little to suggest they wait much longer before making the move. For while it might be rash to suggest that the Sox react to just eight games of evidence to make the decision that Carl Crawford is not a good fit for the leadoff spot, his performance has given them little choice. And if the Sox could use four games of struggle by Ellsbury (a 1-for-16 stretch in Texas and Cleveland) to drop him in the lineup, why would they need more time to make a move with Crawford?

One could counter that it is important for Francona to dig in and remain steadfast with Crawford at a time when he is struggling. Or perhaps it would make more sense to ride things out for another day, especially coming off a game in which the Sox scored eight runs. Doing so could permit the Sox to bump Crawford from the leadoff spot during the forthcoming West Coast trip, where such a decision would receive less publicity.

Yet while the Sox might elect not to make a move immediately, it is hard to see how hitting Crawford leadoff is helping either the outfielder or the team right now.

Here’s the grim reality. Statistically, Crawford has been the worst hitter in the majors this year. After his 0-for-4 day, he ranks second-worst among qualifying hitters in average (.127) and OBP (.172) and worst in slugging (.145) and OPS (.317). He’s tied for the major league lead in games started without a hit (9).

In his seven games as a leadoff hitter, he’s been even worse. He’s 3-for-32 (.094) with no walks and he’s seen just two counts of three balls.

The Red Sox had hoped that giving Crawford Saturday off would permit him to catch his breath and start fresh. Manager Terry Francona met with the outfielder on his day off.

“We talked for a little while. I just wanted to do a couple of things -- reassure him of how we feel, which I think is pretty obvious, but to find out, OK, if I can help, how do I help,” Francona said before the game. “I just thought a day yesterday of being in the cage and not having to take it right to the game sometimes can help. I know he was itching to play yesterday, which I’m really glad. I just think that, hopefully, that’ll help him a little bit.

“Once he gets going, we all know -- I think we all know it; I know I do -- he’s going to get real hot. I just hope it starts today. This is certainly not a guy, that, when he doesn’t hit, you run from. He’s going to be a huge part of our offense.”

Crawford’s career track record suggests that Francona and the Sox will eventually garner the fruits of that approach. But on Sunday, the blueprint didn’t come to fruition.

Indeed, Crawford looked more lost than ever. In his first at-bat of the day, he struck out on four pitches, the last an 86 mph slider that was well off the plate and in the dirt.

Crawford’s day did not get better from there. He swung and missed twice en route to a five-pitch groundout to first.

Then came perhaps Crawford’s most telling at-bat of the game. On a 1-1 count, in his third at-bat against Blue Jays starter Jesse Litsch, Crawford tried to drag a bunt for a hit; Litsch fielded it and flipped to first for an easy out.

That Crawford was bunting for a hit was an indication of his torpedoed confidence. It might seem natural to see the speedy outfielder playing small ball, but to the contrary, he has just 20 career bunt hits. Last year, in fact, he ended a stretch of nearly four years without a bunt hit that had run from June 2006 through May 2010. While he ended last season with three bunt hits, all came in the first inning – typically, at a time when Crawford could reposition fielders for the rest of the game and then look to do some damage.

Crawford’s fourth at-bat featured a first-pitch comebacker. Overall, it was an awful day.

Monday, meanwhile, would not appear to be the ideal matchup for Crawford. He is 2-for-14 (.143) against Jays starter Romero in his career. Meanwhile, Ellsbury (5-for-12, .417) has enjoyed significant success against the Toronto ace. 

The Sox have other leadoff alternatives against Romero as well. With a left-hander on the mound, it’s possible that the team could turn once again to Jed Lowrie, who is 2-for-5 with a walk against the Jays southpaw. J.D. Drew, who has served as a fill-in leadoff hitter in the past, has a .450 average and .560 OBP in 26 career plate appearances against Romero.

Crawford, of course, has endured the most glaring struggles thus far in 2011, but he has not been alone in his difficult start. A number of Sox hitters have endured uncharacteristic struggle through these first two weeks of the season.

That fact, in turn, has led Francona to reconfigure the lineup more times than would be ideal. He has deployed 12 lineups in 14 games.

“If we had one or two lineups, everything was going right. I don't know if that makes sense right now,” he said. “I’ve talked a lot about being consistent. We’re trying to do everything we can to play as well as we can and put guys in the best position. We’ll see. I do know as we get into the season, things normally settle down.”

And when they do, the likelihood is that Ellsbury will be leading off, and Crawford will not be. If the question is when, not if, such a scenario will unfold, then what about both players’ recent performances offers a reason to wait?