PHOENIX -- Left field or first base, it makes no difference to Brandon Allen.
The D-backs' prospect is just happy to be in the big leagues.
Allen was one of four players the D-backs added Wednesday as the rosters expanded for September and he made an instant impact, launching a go-ahead grand slam in Arizona's 5-2 win over San Diego. The 24-year-old was acquired by the D-backs last year from the White Sox and hit .202 in 104 late-season at-bats.
When the club signed first baseman Adam LaRoche in January, it left Allen without a spot on the roster and he spent this season at Triple-A Reno.
A shoulder injury contributed to his slow start at the plate, but Allen finished with a .261 batting average to go with 25 homers and 86 RBIs. In addition, he added versatility to his game, learning how to play left field.
"He's got on-base skills, he's got power and he's got athleticism," D-backs interim GM Jerry Dipoto said.
"I got comfortable," Allen said of playing left field. "I have fun out there, it's fun to play the position and I'm trying to be good at it, real good at it."
Allen certainly looked good when he jumped and crashed into the left-field wall to catch a Nick Hundley drive in the fourth inning. It was the first fly ball hit to him in the big leagues.
It made Reno manager Brett Butler's scouting report to D-backs manager Kirk Gibson look prophetic.
"Bugsy says he's fine," Gibson said. "He's not passive out there. He doesn't have a problem with the wall, dives for the ball. Probably the biggest thing will be his arm adjusting from the infield to the outfield."