You can add longtime reliever Scot Shields to that list.
Shields, who spent his entire 10-year career with the Angels as one of the best middle relievers of his generation, decided to call it a career last March, four months away from his 36th birthday. He arrived in Angels camp at Tempe Diablo Stadium on Thursday, from his home in Detroit, and will be here until Monday as an observer and instructor.
"I'm just here if they need me," said Shields, who was dealing with knee issues toward the end of his career.
Shields is one of three first-time guest instructors the Angels are expected to have -- along with ex-shortstop David Eckstein and ex-catcher Bengie Molina. Mainstays Tim Salmon, Bobby Grich and Mark Langston will also attend, and former closer Troy Percival is tentatively scheduled to be here, too.
The Angels are expecting Salmon to be here Friday and Eckstein to arrive at some point next week.
"It was kind of neat to get to see the guys," Shields said. "The organization does a nice job of bringing some guys back and keeping them involved with the organization."
From 2001-10, Shields posted a 3.18 ERA, a 1.24 WHIP and 155 holds while setting up for closers like Percival, Francisco Rodriguez and Brian Fuentes.
Shields said he could see himself going the coaching route "down the road," but for now he's focused on spending time with his family. He hasn't sought out anybody in particular just yet, but Shields may drop a few tips to young closer Jordan Walden.
"He had a darn good year last year," Shields said. "He's definitely got a bright future ahead of him. ... He's got tons of potential and everything. I enjoyed watching him last year from home. He's got dynamic stuff."