The star center fielder will try to continue tormenting the Royals, and help the AL East-leading Boston Red Sox salvage a split of their four-game series at Kauffman Stadium on Sunday.Ellsbury is a career .400 hitter with 34 runs and 19 stolen bases in 34 games versus Kansas City (60-54).He's batting .429 during a 21-game hitting streak against the Royals, ranking second for the Red Sox (71-48) in the all-time series to Jerry Remy's 28-game run from 1978-82.Ellsbury has extended his run with seven hits in the first three games of this series, including a career high-tying four with a pair of RBI doubles to power Saturday's 5-3 win. He also stole his major league-leading 42nd base."I'm seeing the ball and driving it, putting some good swings on the ball," Ellsbury said. "I feel like I've been swinging the bat well and all you can do is get hard contact."I've put a lot of work into it, into hitting and making good contact."John Lackey (7-9, 3.21 ERA) may appreciate another big performance from Ellsbury since he's 0-3 with a 4.91 ERA over his last four starts. However, the offense has failed to produce any runs in each of his losses, including Monday's 2-0 defeat at Houston.The veteran right-hander limited the Astros to two runs while striking out 10 in six-plus innings, the 10th straight outing he's reached at least the seventh. He also overcame an ankle injury suffered in the second inning while trying to field a soft chopper."He had good secondary stuff and got a lot of key strikeouts when he needed them," manager John Farrell said.Lackey is 2-1 with a 2.00 ERA over his last five starts versus the Royals, but hasn't pitched in Kansas City since Sept. 5, 2009, while with the Los Angeles Angels.Despite Saturday's defeat, the Royals have won 15 of 18, including seven of nine at home while hitting .315 with 49 runs.Billy Butler has a .457 average in those nine home games, and he's 7 for 13 with four runs and three RBIs in this series. The designated hitter is batting .398 with 19 RBIs in his last 22 meetings against the Red Sox at Kansas City.James Shields (6-8, 3.36) tries again for his first home win since April 30 while also attempting to rebound from his worst performance of the seasonThe right-hander is 0-4 with a 4.70 ERA over his last nine games in Kansas City, getting roughed up in Tuesday's 7-0 loss to Minnesota. He was tagged for a season-high seven runs and three homers in six innings and also balked home a run."He just had trouble getting the ball down," manager Ned Yost said. "Command was the issue."Shields didn't have any such issues against the Red Sox on April 20, yielding one run and four hits while striking out eight in six innings before the bullpen wasted his effort in a 4-3 loss.Shields has struggled against Ellsbury over the past three seasons, allowing him to go 8 for 24 (.333) with two homers and two doubles. He's also had a tough time with Will Middlebrooks, who is 3 for 5.Middlebrooks had two hits and two RBIs Saturday, hours after being recalled from Triple-A Pawtucket as the Red Sox give him another chance to become their everyday third baseman.