ANAHEIM -- Rangers starter Drew Smyly allowed too many baserunners and Angels outfielder Mike Trout made him paid for it.

Once again, Trout provided the big blow with a fourth-inning grand slam that carried the Angels to a 5-1 victory over the Rangers on Saturday afternoon at Angel Stadium. It was Trout’s fourth home run in three games against the Rangers.

“I am going to have nightmares about that guy,” Rangers manager Chris Woodward said.

Woodward may lose even more sleep if Texas first baseman Ronald Guzmán goes down with an injury. Guzman had to leave Saturday’s game in the third inning with tightness in his right hamstring and was sent for an MRI. The Rangers will have to wait until tomorrow to know the severity of the injury, and if Guzman has to go on the injured list.

“Hopefully, the damage won’t be too bad,” Woodward said. “We need him. He was feeling pretty good. Hopefully it’s just tightness, but it didn’t look very good.”

Guzman felt the muscle running out a double to right field. The ball had caromed away from Peter Bourjos, and the Angels’ right fielder tumbled to the ground. That gave Guzman a chance to go for a triple, but he seemed to feel something in his leg and pulled up at second base.

The Rangers are hoping for a quick evaluation so they can determine if a roster move will be needed before Sunday’s game. There is a possibility the club could hold off through Monday’s off-day before making a decision.

Triple-A Nashville first baseman Matt Davidson would be the logical candidate if the Rangers need to make a move, but he is not on the 40-man roster. Patrick Wisdom is on the 40-man, but he is more of a third baseman.

Texas doesn’t carry a true backup first baseman. Logan Forsythe, who started at third base on Saturday, shifted to first after Guzman left the game. Asdrúbal Cabrera, who was supposed to have the day off, took over at third. Joey Gallo has experience at first base, but he hasn’t worked out there at all this season. Woodward is hoping to keep him in the outfield.

“I’ll get back to you on that one,” Woodward said. “I don’t want to do that. I’d rather him stick to the outfield. If it’s really bad, that’s a different story. But if it’s going to be a short time or a short [injured list] stay, I don’t foresee Joey playing first.”

Guzman exited a scoreless game. Smyly was in constant trouble with seven baserunners in the first three innings, but he kept finding ways to get out of jams. It caught up with him in the fourth.

Smyly was at 74 pitches going into the inning and he opened by getting Kevan Smith to ground out. Bourjos smashed a grounder down the third-base line that Cabrera backhanded and bobbled before making a strong throw to get the out call at first. But the Angels challenged and got the reversal for an infield hit.

Smyly, in a left-on-left matchup, then walked Tommy La Stella, the No. 9 hitter, and David Fletcher singled to load the bases. That brought up Trout, who saw three straight fastballs and hit the third one 458 feet beyond the left-field wall. It’s the third longest home run for Trout since Statcast was introduced in 2015.

"I think I made improvements from last start,” Smyly said. “Still not good enough. I've got to be more efficient. I'm struggling having quick innings, kind of putting guys away. Yeah, I gave up the grand slam to Trout, but it seems like every inning I've pitched this year has been runners on bases, stressful innings.”