BOSTON — The presumed battle between John Lackey and Erik Bedard for a third start in the opening round of the playoffs is one thing. There are other spots still up for grab as the Red Sox advance toward a likely postseason berth and the construction of a roster that will go toe-to-toe in a best-of-five series.

The at-the-buzzer addition of first baseman-outfielder Conor Jackson, as well as earlier signings of wayward speedster Joey Gathright and veteran lefty Trever Miller, are all part of that formula, or at least transactions that will push those who are ahead of them on the food chain.

Chief among those is Jackson, the right-handed bat everyone wanted. Well, not THE right-handed bat, but A right-handed bat. That doesn't mean Darnell McDonald or Mike Aviles will be left at the curb when the club turns the corner to October, but competition has increased for the utility folk vying for one of those precious spots next month.

Although the future remains uncertain, Jackson is looking forward to the opportunity.

"Playing in the playoffs is a feeling that's unparalleled to anything," said Jackson, who appeared in the postseason with Arizona in 2007.

Jackson rose as a promising first baseman in the Diamondbacks system and slugged 46 home runs in parts of six seasons for them before joining Oakland in a trade last June. He has not quite lived up to his former top prospect status, in part due to physical issues, but his power potential against lefties will give Terry Francona one more guy to choose from down the stretch. And maybe in October if he stands out in a very muddled right field situation.

"Some of that's going to be determined by how they swing the bat," said manager Terry Francona when asked about playing time at that position. "There's no getting around it. How you figure that out and how you let a guy get hot enough to where they can swing the bat, that'll be our challenge, and we’ll work on that."

There’s precedence for these late additions making an impact in October.

Think back to Bobby Kielty. He was acquired as an unheralded free agent in August of 2007 and ended up providing a pair of RBIs in the ALCS and a home run in the World Series. You never know where a contribution can come from, and that’s why late-season additions like Jackson, while rather cosmetic on paper, can have some impact down the road.

The same can be said for Gathright, plucked from the independent Yuma Scorpions on Wednesday.
Think back to Dave Roberts. He was picked up at the trade deadline in 2004, played solid ball for 45 games down the stretch and then etched his name in Red Sox lore with a stolen base for the ages against the Yankees in the ALCS. Gathright's once-promising career has tailed off, but he's a burner that could use his legs in a big spot down the road.

In fact, Gathright made the 2009 playoff roster with the Red Sox after being picked up on Aug. 29 of that year, almost two years to the day. He appeared in one game, stole one base and scored one run. That kind of a contribution can make a difference in a short series.

As for Miller, there's never not a need for more left-handed options out of the bullpen, especially for a team that hasn't had many this season. Franklin Morales and Felix Doubront are the two southpaws in the pen right now.

Neither Gathright or Miller are on the 40-man roster, so a shuffle would have to take place at some point for them to be contributors in October. For now, they only provide depth, but along with Jackson have a chance to audition for a more important role on a much bigger stage.