Alfonso Soriano's defense getting special attention

MESA, Ariz. – Looking for a matchup to watch to get an idea of the impact of the Cubs’ new field staff?

Then pay attention to Alfonso Soriano vs. The Wall.

‘‘We’re spending a lot of time on that,” said coach Dave McKay, who was in charge of the outfield and baserunning this spring. ‘‘He knows we’re going hard after everything. A ball over your head, don’t assume anything. Go hard, get it to the cutoff man. And he’s playing the game right.”

How much improvement the Cubs can make from their major-league-worst fielding last year will depend primarily on improvement at three spots.

One involves new third baseman Ian Stewart. Another involves the continued development of shortstop Starlin Castro.

Then there’s the 36-year-old Soriano, who has looked out of position in the outfield ever since the Washington Nationals moved him there in 2006.

‘‘They just put me out there, and I had to figure it out,” said Soriano, who still throws like an infielder but finally has gotten rid of the unnecessary hop on routine fly balls that has led to two errors with the Cubs. ‘‘When people were taking BP, I’d just shag. That’s how I worked on it.

‘‘With Dave, it’s totally different. I tell you, he’s a smart guy. I’m so happy he’s working with me in the outfield.”

McKay hasn’t turned Soriano into a Gold Glove contender. And to be fair, Soriano improved noticeably the last two seasons when he finally began doing extra work.

But a daily emphasis on basics such as hitting the cutoff man – ‘‘he tells me that every day before the game,” Soriano said – and properly fielding ground-ball hits and catching fly balls seem to have made him more consistent.

‘‘Soriano’s played a pretty good left field so far,” McKay said.

Soriano has long admitted an aversion to outfield walls, in particular a fear of the bricks at Wrigley Field.

But he’s bracing for the realities of a new approach.

‘‘I haven’t had a fly ball yet at the wall [this spring],” he said. ‘‘I have practiced it in BP, but I want to have one in a game.

‘‘We’ll see what happens.”

LaHair iffy for opener

First baseman Bryan LaHair, who was held out of the Cubs’ last four exhibition games because of back tightness caused by a bulging disc, could be a game-time decision for the opener Thursday.

‘‘I don’t think it’s a [disabled list] thing or anything like that,” said manager Dale Sveum, who anticipates LaHair playing sometime during the three-game series against the Nationals. ‘‘Hopefully, we’ll get a chance to see him take BP [Wednesday] at the workout and see what happens on Opening Day.”

LaHair, who broke camp in the big leagues for the first time, remains hopeful he’ll play Thursday.

‘‘I’m getting better,” he said. ‘‘I’m tough mentally, so I’m just rolling with the punches. I’m focusing in on whatever that first game’s going to be, whether it’s Thursday, Saturday, Sunday. Whatever it’s going to be, that’s what I’m getting ready for.

‘‘And the most important thing is that I get healthy, and once I’m healthy, I’ve been known to stay healthy.”

Pen note

The Cubs planned to break camp with eight relievers for seven bullpen spots and make the final decision near the deadline for setting rosters Wednesday.

‘‘That’ll be an 11th-hour decision,” Sveum said.

The Cubs still might acquire a pitcher before then. Another factor is the roster rules involved in Rule 5 picks such as Lendy Castillo.