That would be J.J. Hardy, the Orioles shortstop who has been hitting and playing the field in a way that has manager Buck Showalter raving about him.
Hardy has had 10 hits in his last three games going into Thursday's single-admission doubleheader against the Rangers, including five in Sunday's 17-inning victory over the Red Sox.
Hardy also saved that game for the Orioles with a relay throw to the plate in the 16th inning that cut down the Red Sox's Marlon Byrd trying to score the winning run.
"What a game J.J. had," Showalter said after that game. "Good gosh, he played shortstop the way you want to see it played."
"The first month was a struggle for me," Hardy said. "I was really trying to find my swing, really trying to get comfortable up there. That last game in Boston, that 17-inning game, was the first day really this whole year that I've felt comfortable. I've just been able to kind of feed off that."
After getting those five hits Sunday against the Red Sox, Hardy had three hits in the first game and two in the second of this four-game series with the Rangers, raising his average from .187 to .244.
"I feel more comfortable. I feel like I'm seeing the ball a little better these last three days," he said. "People were saying I was hitting the ball hard that first month, but I didn't feel like I was. I felt like I was out in front, late, my timing was off, I just wasn't seeing the ball good."
Hardy's nice little surge pales, of course, in comparison to what Hamilton is doing.
The Rangers outfielder's four home runs, to go with a double and eight RBIs in Tuesday's game, gave him five home runs in his last six at-bats, raising his season totals to 14 homers, 36 RBIs, a .406 batting average and .840 slugging percentage.
All were Major League bests before Wednesday's games.
Rangers: Cruz quietly swinging hot bat
In addition to Hamilton, right fielder Nelson Cruz has been hot in this series with a pair of three-hit games. He has a career batting average of .385 against the Orioles. That's the second highest among opponents with at least 100 at-bats against them, behind Adrian Gonzalez (.421).
Orioles: Pitching tops despite minor setback
The Orioles' 3.21 ERA led the American League and was fourth best in the Major Leagues on Wednesday, behind Washington (2.64), St. Louis (3.11) and Miami (3.20). Baltimore saw its team ERA jump from 2.78 to its current mark in the last two games.
Matt Wieters has hit safely in nine straight games (.342/.419/.579), one shy of his career-long hitting streak (May 8-21, 2011).
The Rangers and Orioles played a doubleheader at Camden Yards last season, but when they played two there on Aug. 22, 2007, the Rangers beat the Orioles, 30-3, scoring a record number of runs in a Major League game played since 1900. The barrage included grand slams by Marlon Byrd and Travis Metcalf, two home runs and seven RBIs by Ramon Vazquez and a seven-RBI night by Jarrod Saltalamacchia.
The pitching matchups for Thursday's games will have the Rangers' Colby Lewis against the Orioles' Wei-Yin Chen in Game 1, which is scheduled for a 4:05 p.m. ET start, and Rangers left-hander Derek Holland against Tommy Hunter in Game 2, which won't start before 7:05.
Hunter was optioned Monday and will be recalled for the Game 2 start. The Orioles will have to make a roster move in between games because Hunter can only be activated in an injury situation in order to avoid the minimum 10-day stay in the Minor Leagues after having been optioned.