He's filling the roster opening created by the death of pitcher Nick Adenhart.
"It's very difficult. Very difficult," said Willits, his lower lip quivering while he spoke to reporters. "Anytime you get called up, you're happy to go up. But under the circumstances, it just didn't feel right. Nobody wants to talk about a situation like that, with the roster spot being open.
"But I remember talking to my wife and telling her: 'I really hope it's not me,' because of how hard it is."
Willits got the word from Salt Lake manager Bobby Mitchell on Friday night after the Bees' season opener.
"I don't feel like I'm replacing him. I don't think anybody's ever going to replace him," Willits said. "I know everybody as an organization has tried to move on, but it's so hard when it's only been a couple of days. We not only lost a teammate, but we lost a friend and the world lost a good guy."
The Angels have had a grief counselor on hand to help players and front office personnel deal with the tragedy.
"It might be a tough situation for [Willits], but I don't think you can approach it as trying to replace Nick because of what's happened here," manager Mike Scioscia said. "Reggie got the call now, but there's obviously going to be a lot of roster moves all season.
"Nobody wants to get the call to the big leagues under these circumstances. But Reggie's here, he's got a role to play, and that's what it is," Scioscia said.
This is Willits' fourth stint with the big club. He started the season in the minors because of a glut of outfielders including Vladimir Guerrero, Torii Hunter, Bobby Abreu, Juan Rivera and Gary Matthews Jr.
After pitching six scoreless innings in a no-decision against Oakland on Wednesday night, Adenhart was riding in the passenger seat of a Mitsubishi Eclipse when the vehicle was broadsided by a suspected drunken driver in a minivan at a nearby Fullerton intersection. A few hours later, he was pronounced dead at a hospital in Irvine.
"For something to happen that abruptly to somebody so young with such a bright future ahead of him, it's just hard," Willits said. "I consider Nick a friend, so it's very hard. We all came up through the system, and we're all hurting and helping his closest friends down there cope with this at the same time.
"Brad Coon and Bobby Wilson were really close to him, and they found out because Nick's mom called them," Willits said. "So it was a pretty tough phone call. It caught everybody off guard. It's not something I can put into words very good."
The Angels are keeping Adenhart's locker just the way it was when he left the ballpark for the last time.
"That was the first thing I looked at," Willits said.
He added, "He's one of those guys who everybody thought was real laid back -- which he was -- but he might have been the funniest guy in the room. When he signed, he was 18 years old. He'd come so far. He probably grew up faster than I did. And to see how fast he came along -- not just as a baseball player, but as a person and as an individual."