That all changed Tuesday night, when Guillen doubled his RBI total and the Royals reached a season high in defeating the Texas Rangers 9-5.
"For this offense to come around, I had to start swinging the bat better. That's why they got me," said Guillen, who signed in December with Kansas City as a free agent.
The Royals have won three of their last four games after snapping a seven-game losing streak. Texas has lost 14 of its last 18 games to fall to a major league-worst 9-18 record on beleaguered manager Ron Washington's 56th birthday.
Guillen drove in the Royals' first run with a first-inning fielder's choice, singled to produce Kansas City's two runs in the second and hit a two-run home run in the fourth.
"He swung the bat very well. The more he does that, the better off we'll be. His best at-bat was the base hit to left, when he battled back," Royals manager Trey Hillman said.
Texas starter Jason Jennings (0-5) gave up eight hits and five runs before leaving with no outs in the third inning because of ulnar nerve irritation in his right arm. Given a 7-2 lead, Brett Tomko couldn't last more than 3 1/3 innings. He gave up five runs and seven hits.
"I felt a sharp twinge in the back of my elbow," Jennings said. "It happened on the base hit to [Ross] Gload when I threw a changeup. I threw a fastball on the first pitch to the next guy, and felt it again.
"The doctor said it was a nerve/muscle strain. We'll see how sore I am [Wednesday]."
Ron Mahay (1-0) entered the game with the Royals ahead 7-5, a runner at second base, and one out. He retired Josh Hamilton and
Milton Bradley to end the threat. Mahay and three other relievers held the Rangers scoreless over the final 5 2/3 innings.
The Royals never trailed in the game. They took a 3-0 lead in an eventful first inning that included Washington racing out of the dugout to protest when home plate umpire Bill Welke called Grudzielanek safe at home on a tag play. That would have been the second out.
"We got him out," said catcher Jarrod Saltalamacchia. "[Welke] just missed it. But that was only one run. We needed to stop more of them."
In the bottom of the first, Welke ejected leadoff batter Ian Kinsler for arguing over a called third strike.
Then Guillen became Texas' biggest problem. In his previous visit to Rangers Ballpark last August, he had seven hits, including two homers, in four games for the Seattle Mariners.
"I like to get hits in any ballpark," Guillen said. "I was lucky to get that hanging curve. When you're a hitter, you hope for something like that. It happened today twice."
For Texas, five players drove in one run each, and five scored a run apiece. Brandon Boggs made his major league debut in the fifth inning and went 2-for-2 with a walk.
Texas SS Michael Young extended his hitting streak to 13 games with a third-inning single. ... The Rangers, with the most errors in the American League, took infield practice before the game and didn't commit an error. Washington said he couldn't remember the last time one of his teams had taken infield practice. ... Rangers LHP
Kason Gabbard, on the disabled list because of a stiff back, will throw on the side Wednesday. He said he was told he would make an injury-rehab start Saturday at high Class A Bakersfield and could return to Texas' rotation May 8.