MINNEAPOLIS — On a day the Minnesota Twins added slugger Kendrys Morales to the roster, they showed they might need more pitching help.
Starter Samuel Deduno was pulled in the fourth inning, relievers allowed three home runs — including two grand slams — and the Twins lost 14-5 to Houston on Sunday as the Astros won two of three in series.
"Today, I didn't have anything," said Deduno, who allowed five runs and walked four before he was lifted after loading the bases in the fourth inning. All three of those runners scored.
Anthony Swarzak pitched three scoreless innings, but Brian Duensing, Casey Fien and Glen Perkins gave up a combined eight runs. All those add-on runs came after the Twins had closed to 5-3 after five innings.
Chris Carter, George Springer and Jon Singleton homered off the Twins' relievers, with Carter and Singleton each hitting his first career grand slam.
The only other time two Astros players hit grand slams in the same game was July 30, 1969, at New York when Denis Menke and Jimmy Wynn both hit slams in an 11-run ninth inning against the Mets.
Dexter Fowler also homered for the Astros.
"It puts more strain on the opposing pitchers," Astros manager Bo Porter said on his team's new-found power stroke. "They feel like, 'I can't make a mistake here, I can't make a mistake here.' That can drain on a staff."
Darin Downs (1-0) got the last eight outs as the third reliever to follow starter Colin McHugh, who fanned six and allowed one run over 4 1/3 innings. He walked five and was removed after throwing 101 pitches.
Trevor Plouffe and Josh Willingham hit RBI singles as Minnesota made it 5-3 in the fifth, but couldn't get any closer before Carter and Singleton powered the game away.
Morales, who declined a contract offer from Seattle in the offseason, signed a one-year deal pro-rated to slightly more than $7.4 million for the rest of the season. Because he's out of options and not injured, he'll stay on the Twins big-league roster and probably make his Twins debut during the upcoming road trip to Toronto, Detroit and Boston.
"That does a lot just for the guys in here about how (people in the front office) reward our play so far," Twins closer Glen Perkins said of the signing. "We have a similar record to what we had last year, but I think we're a lot better team."
Houston batted around in the fourth inning, scoring three runs after Deduno (2-4) loaded the bases with nobody out by walking two batters and hitting another.
The Astros have won seven of eight on the road and 11 of their last 15 overall as they try to snap a three-year streak of losing 100 games.
Minnesota is now three games under .500 and in need of a string of quality starts from its rotation.
Deduno saw his ERA rise to 4.45 with Sunday's outing. As a group, Minnesota's starters are 19-25 with a 4.97 ERA.
McHugh struck out four batters in a row during one stretch and extended his scoreless innings streak to a career-high 16 2-3 before Eduardo Nunez homered in the fourth.
Springer, named American League rookie of the month after hitting 10 home runs in May, led off the eighth by hitting his second homer in three games.