Morrow surrendered a solo home run in the second inning and a three-run blast in the third inning, wiping out what had been a two-run Mariners lead as Seattle dropped a 6-4 decision to the Rangers before 34,874 at Safeco Field.
The setback put the Mariners 4 1/2 games behind the AL West-leading Rangers.
The second game of the four-game series was a tale of two innings.
Morrow, making his sixth start since being moved out of the closer role -- following back-to-back blown saves against the Rangers on May 13-14 in Arlington -- zipped through the first inning with just six pitches.
He was rewarded with a two-run lead in the bottom of the inning.
Ichiro Suzuki led off with a single into center field and scored easily when Russell Branyan drilled a double into left-center. An infield out advanced Branyan to third, but he was thrown out at the plate when he tried to score after Ken Griffey Jr. hit a grounder to second baseman Ian Kinsler.
It appeared that the Mariners would have settle for one run, but Franklin Gutierrez lined a double into right-center. As the ball rolled to the wall, Griffey chugged around the bases as fast as his 39-year-old legs would take him and he scored standing up.
Several teammates cooled him off with towels in the dugout and Ichiro did his best impression of Junior rounding third and coming home.
But the good vibes began going sour in the second inning when Hank Blalock -- Morrow's main nemesis in Texas -- slugged a one-out home run to right-center.
And then came the third inning, which started out well for Morrow. He retired the first batter and then walked Omar Vizquel on a full-count pitch. Then he issued a free pass to Kinsler.
All-Star third baseman Michael Young was more impatient, hitting the first pitch he saw into the first row of seats in right field for his 11th home run of the season.
Ichiro made a gallant effort to keep the ball in play, but couldn't quite reach it.
"I was looking for something I could get in the air and kind of drive a little bit," Young said. "At first and second with one out, anything I roll over right there is going to be bad news, it's probably going to be a double-play ball, so I'm looking for something I cannot necessarily hit in the air but hit hard and hopefully find a gap."
He missed a gap, but found the seats and the Mariners were suddenly behind by two runs. They eventually fell behind by four before scoring their final two runs in the eighth inning.
"It was a tough game, obviously," manager Don Wakamatsu said. "I thought we battled to the end."
But what's the deal with Morrow, who is 0-4 with a 5.28 ERA heading into the All-Star break?
"We've seen it in different starts this year," Wakamatsu said. "He has a tendency to lose it a little bit. We had a conversation on the bench about what causes that."
It befuddles Morrow as much as anyone.
"You have to step off and slow down," he said. "I guess I was missing with a little of everything."
Three of the four walks he issued during his five-inning stint came in the third inning, when he needed 26 pitches to get three outs.
He stuck with the hard stuff, fastballs and sliders, when he should have changed speeds and tried to get the Rangers to back off.
Against the Rangers, "you have to be able to offset your hard stuff with something soft," Wakamatsu said. "I don't think he had a feel for his curveball and didn't throw it much."
Morrow said he couldn't remember throwing a curveball, or even getting a curveball sign from catcher Kenji Johjima.
"When he throws a good one, it's an awfully good pitch," Wakamatsu said. "Looking down the road, if he can harness that, I think you are going to see a lot better pitcher."
If not, he will continue to struggle.
The Rangers are a fastball-hitting team and they added three home runs to their season total. Besides Blalock (No. 18) and Young (No. 11), just-named All-Star Nelson Cruz hit his 21st off rookie right-hander Shawn Kelley, who is still not flashing the same magic he had before suffering a strained left oblique.
He said he feels good, physically and mentally.
"When you go 2-and-0 to a hitter like Cruz," he said, "he's going to hurt you."
Kelley fed Cruz a fastball, left it about belt high, and it was hit a long way.
The Rangers now have hit 130 home runs this season, compared to the Mariners' 82.
Seattle got a three-hit game from Griffey and two from Ichiro.