The Tigers won't comment on the reason for the absence, but according to various reports, Sheffield is involved in a legal proceeding with his former agent. Manager Jim Leyland gives each of his players a day during camp, usually at their selection, during which they can be completely away from the team. Sheffield took his day Wednesday.
Though Sheffield hasn't played since Monday against the Devil Rays, his days off on Tuesday and Thursday were road trips on which he wasn't scheduled.
"All of our players are given a day or two in Spring Training," president/general manager Dave Dombrowski said Thursday afternoon. "A lot of them have already been gone. They all get a day."
Later Thursday, Sheffield's current agent, Rufus Williams, said in an email to The Associated Press that Sheffield would return "as soon as he can. We expect that to be this weekend."
"It is Gary's preference to be on the field, to be with his teammates, playing in the preseason and preparing for a World Series run with the Detroit Tigers," Williams told the AP. "It is difficult for him to be involved with this in general, but clearly more difficult to be required to deal with it during any part of the season."
Sheffield was previously represented by Scott Boras. The legal proceedings were first reported earlier this week by the New York Times.
Sheffield had played regularly until this week. The 38-year-old has 33 plate appearances, which ranked among the team leaders until a couple of days ago. As of Thursday, he was fifth on the team behind Carlos Guillen, Curtis Granderson, Brandon Inge and Ivan Rodriguez. Sheffield's at-bat total is lower compared to teammates in part because of his team-high seven walks.
Both trips Sheffield missed were to Florida's Atlantic Coast -- Tuesday at Vero Beach, then Thursday night at Viera. Sheffield, who lives in Tampa, had made five of the previous six road trips, all around the Tampa Bay area.
"He's been in about five [trip] in a row," manager Jim Leyland said Wednesday. "He's [almost] 40 years old. He's got as many or more at-bats than just about anybody."
Eischen works on arm strength: Lefty reliever Joey Eischen, who hasn't thrown in a game since March 6, is working on building his arm strength. He threw a bullpen session with pitching coach Chuck Hernandez watching on Thursday, his second one this week, and felt encouraged.
Eischen is nine months removed from surgery to repair a torn rotator cuff, a procedure that normally takes longer from which to recover. Eischen has been working hard in an attempt to speed up the strengthening process, but in retrospect, he pushed it a little too much. The movement on his pitches is there, he said, but his velocity is still building. He was pitching in the lower 80s earlier this month, compared to mid to upper 80s over the last couple years when he was pitching with a bad rotator cuff.
"Second week in [camp], I was feeling dead, and my ball started dying," Eischen said. "My throwing sessions are going much better now than at the beginning of spring. Every time out I've taken a step forward."
Eischen has more energy since paring back his workouts and focusing on throwing and running. Meanwhile, Tigers coaches have remained patient with the non-roster invitee.
"The tough part about this is being patient," Eischen said, "and that's one of my weak suits. They're doing right by me. They've gone way out of bounds to make me feel comfortable, to do what I need to do, to accommodate me, which in this day and age of baseball is seldom seen anymore."
Leyland said Thursday that Eischen would probably open the season in Lakeland until he regains his velocity. Eischen, for his part, would be open to it in order to show what he can do at full strength.
"The only way I'm going to go home is if my arm goes backwards," Eischen said, "if my arm blows out or something tells me that it's not going to come back. Right now, there's just been nothing [to suggest that]."
Dingman update: Craig Dingman is scheduled to throw to hitters for the first time on Friday, the next step in his comeback from arterial bypass surgery last spring. Dingman, whose camp was interrupted by blood clots in his shoulder earlier this month, will throw a 10-minute session against Tigers hitters after completing three bullpen sessions in just over a week. He began throwing all his pitches in his last session earlier this week.
Monroe making up time: Craig Monroe is catching up on at-bats and trying to run under control now that he's back in the lineup. He missed nearly a week after his left knee flared up with patellar tendinitis.
There's no way to completely cure it, Monroe said, but he has to be diligent about treating it.
"It's going to be a maintenance thing," Monroe said. "You're getting to a point where it's more [work]. It's not going [to the weight room] just to work on the upper body or lower body. Now it's targeting certain things to keep you healthy. I think every big player does that. I watch Guillen. I watch [Magglio Ordonez]. All these guys have [training] programs."
Coming up: The Tigers are at home on Friday for a 1:05 p.m. ET game against the Phillies at Joker Marchant Stadium. Mike Maroth is scheduled to start, followed by Jose Mesa, Edward Campusano, Jason Grilli, Bobby Seay and Yorman Bazardo. Jon Lieber, Antonio Alfonseca, Clay Condrey, Brian Sanches and Kane Davis are expected to pitch for Philadelphia.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.