The left-hander pitched parts of seven seasons in Minnesota but had run-ins with Twins manager Ron Gardenhire last season over how he was used. The Angels acquired Romero in exchange for Minor League infielder Alexi Casilla in a trade last December.
Romero said he spoke with Gardenhire after the trade and has put the episode behind him.
"It was a respectful thing," said Romero, who was back in his old park Tuesday as the Angels opened a three-game series here. "Everyone can disagree. It's like with a parent -- you can disagree with a parent. It was a family thing."
Romero added that he learned from the experience and has matured. The biggest lesson, Romero said, was facing that the manager is the boss.
With the Twins, Romero enjoyed his best season in 2002 when he was 9-2 with a 1.89 ERA in 81 appearances while also earning one save. Last season, Romero posted a 4-3 mark with 3.47 ERA in 68 games.
His role with the Angels is evolving. The lone lefty in the bullpen, Romero is second to Scot Shields as a late-inning setup man to closer Francisco Rodriguez. He is also called on to get the tough left-hander, but the Angels would prefer to not use him as a one-batter specialist.
Through his first five games with the Angels this season, Romero had not allowed an earned run while posting a 1-0 record in 4 2/3 innings.
"Right now, I have to take care of business with my new team," Romero said. "If you're comfortable with your surroundings, you will pitch a lot better."
One that got away: The Twins have been happy with Casilla, who is playing at Fort Myers, the Twins' high Class A affiliate. Manager Mike Scioscia liked him as well.
"He has a terrific amount of ability," Scioscia said. "We needed that left-handed influence in the bullpen, but it came at a price.
Casilla is hitting .340 with five doubles in 11 games for the Miracle.
Trainer's room: Juan Rivera was out of the lineup again Tuesday with a left rib-cage strain while Tim Salmon was available as a pinch-hitter as he works through a slight stain of his right hip flexor muscle. Rodriguez was available after a day out of action with a right hamstring strain.
Rivera is hitting .229 with two homers and five RBIs in 12 games this season.
"Rivera is feeling better," Scioscia said. "It is a tweak, but it has improved."
Salmon left Sunday's game after collecting two singles. It was his seventh start of the regular season but the first time this year he's suffered a setback. Salmon had two surgeries in 2004, one to his left knee and another to his left shoulder.
"I feel good right now," said Salmon, who is hitting .333 with a double, triple, two homers and two RBIs. "It was a little stiff yesterday. I can still feel a little bit of it."
Shuffling: Garret Anderson was the designated hitter Tuesday, with Chone Figgins starting in left field for the first time this season. Scioscia said he wanted to get Anderson off his feet given the artificial surface at the Metrodome. He added that Vladimir Guerrero will likely DH at some point during the three-game series.
Maicer Izturis started at third base and batted sixth.
Suspended: Angels farmhand RHP Karl Gelinas was one of four Minor Leaguers to receive a 50-day suspension Tuesday for violating baseball's drug policy. Angel Rocha, a pitcher in the Diamondbacks organization, was given a 100-day suspension for a second offense.
Gelinas, a 47th-round pick in 2003, was 0-2 with a 7.59 ERA in two games at Class A Rancho Cucamonga this season.
"It is big, but that is the purpose of it," Scioscia said. "Everyone knows the ground rules and all of our guys have been briefed on it. It is unfortunate."
On the farm: Triple-A Salt Lake was snowed out in its series finale against Portland. ... Second baseman Howie Kendrick is on an 11-game hitting streak and leads the Bees with a .449 batting average through 11 games. ... Right-hander Kevin Gregg has not allowed a run in three games, covering 10 innings.
On deck: The Angels will face the Twins in the second game of a three-game series at 5:10 p.m. PT on Wednesday. Right-hander Ervin Santana will start against Minnesota right-hander Kyle Lohse. Right-hander Bartolo Colon will face the Twins on Thursday.
