Tulowitzki looks to continue his San Diego surge on Saturday as the Rockies try to hand the last-place Padres a ninth straight loss.Hitless in his last 11 at-bats coming into Friday's series opener, Tulowitzki drove in a run with a groundout and added an RBI single to lift Colorado (65-73) to a 3-0 win. Tulowitzki is hitting .429 (12 for 28) with a homer and 10 RBIs this year in San Diego."Any time you come here and play, you know it's going to be an offensive struggle," he said.The Rockies have scored just 27 runs while posting a 5-2 record at Petco Park.Tulowitzki has just two hits in eight career at-bats against Padres scheduled starter Cory Luebke, but both were homers. Colorado's star shortstop is hitting .303 -- a 12-point drop from 2010 -- but he's also hit 28 homers and driven in 96 to exceed last season's totals with 24 games to play.Luebke (5-7, 3.01 ERA) will make his first start of the season against the Rockies. The left-hander was 0-1 in two starts last September versus Colorado, surrendering eight runs and 15 hits -- including three homers -- in 9 2/3 innings.In six relief outings this year, however, Luebke held Colorado to two hits and a walk in 7 1/3 scoreless innings.Since moving into the rotation in late June, Luebke is 4-5 with a 2.89 ERA in 12 starts, allowing three runs or fewer in 10 of them. The Padres have gone 7-3 in those games.Luebke suffered his first loss in five starts Sunday against Arizona after yielding three runs and six hits in 5 1/3 innings of the 6-1 defeat.Jason Bartlett had three hits Friday and has gone 9 for 19 during a five-game hitting streak against the Rockies, but San Diego (60-78) is batting .208 while totaling 11 runs during its eight-game overall skid.Colorado's Alex White (0-1, 7.50) hopes to extend the Padres' offensive woes while making his third start since joining the Rockies in the deadline-day trade that sent Ubaldo Jimenez to Cleveland.White has surrendered five runs and seven hits over six innings in each of his first two games with his new club. He permitted three of his season-high six walks in the first inning of Monday's 5-1 loss to Arizona after issuing 10 bases on balls over 21 innings in his first four major league starts."The two starts I've had here have been frustrating. But I'm trying to prepare myself to be a part of this organization for a long time. That involves me being a good-to-great pitcher, for many years," White told the Rockies' official website.He will be facing a Padres team that's averaging 3.72 runs per game and has been blanked 18 times this year.