Off-field issues drive fantasy general managers crazy. You can crunch numbers and make their own statistical projections, but you can’t account for personal problems that often derail players.

There is no formula for gauging the impact of substance abuse, psychological problems or other such issues. Those afflicted become X-factor players, offering big upside but considerable risk.

Tigers slugger Miguel Cabrera threatened to join this unfortunate club after getting arrested at the end of last season. During the final weekend of the season -- when Detroit had a critical series with the White Sox -- Cabrera went on a drinking binge.

It ended when police busted him on a domestic violence beef. This winter he owned up to a drinking problem and sought treatment.

Will that professional help allow Cabrera to remain on his highly productive path?

“I can't answer that question,” Tigers president Dave Dombrowski said. “I will say that he is in a much different place mentally, for what he has done. I think he is also in a better place family-wise. He's worked very hard. He's done a lot.”

Cabrera expects his off-field progress to translate onto the field. “I think I'm going to be a better player this year,” he said.

Fantasy GMs want to hear that, since Cabrera provided machine-like production since establishing himself as an everyday player. His 103 RBI last season were his fewest in six full major league seasons. He hit 33 or more homers in five of those seasons.

He lost some fantasy value by moving from third base to first base, but his statistical consistency makes him a high-round selection – IF he keeps his life in order. So far he is doing and saying all the right things, but you’ll want to keep an eye on him.

Here are some other X-Factor players to evaluate with care before your draft:

Manny Ramirez, OF, Dodgers: After serving a 50-game suspension for violating baseball’s performance-enhancing drug policy, he hit just 13 homers for the remainder of the season. He went just 17-for-78 during September and October. A nagging wrist injury cut into his production, as did the rust he accumulated while sitting idle.

And he lost the spark he showed the summer before while hitting .396 in 53 games for the Dodgers. “Some of the fun was out of the game for him, and I hope it will be back and the results will return as well,” Dodgers owner Frank McCourt told MLB.com. “Not that he didn’t bring it upon himself. He did. But he has to move on, and I think he will.”

Rick Ankiel, OF, Royals: Back in 2008, Ankiel smacked 25 homers and drove in 77 runs for the Cardinals. After losing his pitching career to the dreaded Steve Blass Disease – acute wildness caused by a mental block – he made a nice transition to the outfield. He seemed poised for a breakout year in ’09.

But he fell apart instead, in part due to mechanical issues linked to his spectacular outfield wall crash. The more he struggled at the plate, the less confidence he showed. His season died in August, when he batted .176. As a hitter, was he developing the same sort of mental blocks that ruined his pitching career?

Milton Bradley, Of/DH, Mariners: He was most comfortable in Texas, where he hit 32 doubles, 22 homers, batted .321 and drove in 77 runs. His on-base percentage (.436) and OPS (.999) led the American League that season. But his career-long anger management issues made him a poor fit in Chicago, playing for the high-profile Cubs. Manager Lou Piniella isn’t exactly the nurturing sort, which added to Bradley’s woes. The Cubs sent him home in September to keep him out of the clubhouse.

Seattle should offer safe haven. He will get to play with one of his idols, Ken Griffey Jr. “I'm just looking forward to it,” Bradley told reporters. “He's had an outstanding Hall of Fame, illustrious career. He's always conducted himself in a professional manner and represented the game well. And hopefully, those characteristics and qualities can rub off on me.”

Lastings Milledge, OF, Pirates: He has just about as much talent as anybody in the game. Pittsburgh is committed to giving him a full workload this season. If he can set aside his various off-field adventures and focus on the job at hand, he could make himself extremely valuable.

The Pirates acquired him from the Nationals last season, then sent him to the minors to rehab an injury and improve his work ethic. It seemed to work. In 220 at bats in Pittsburgh, he hit .291 with 11 doubles, four homers, 20 RBI and six stolen bases. He has become a nice fit on this young and increasingly talented team.

“I know this is going to be an important year,” Milledge told the Pittsburgh Tribune-Review. “I'm expecting a lot out of myself. I've been putting in the work, because I think this year could set up the rest of my career.”

Gary Matthews Jr., OF, Mets: Back in 2006, he hit .313 with 19 homers and 79 RBI for the Rangers. That got him a big deal in Anaheim, where he faded badly. He hit .252 with 18 homers and 72 RBI in his first season with the Angels, then fell into a platoon role after that team signed Torii Hunter.

A SI.com report in 2007 implicated him in a HGH investigation, although a MLB investigation proved there wasn’t sufficient evidence to punish him. Matthews drove in just 96 runs the last two seasons combined and then moved to the Mets to add depth as Carlos Beltran recovers from knee surgery.

“He has had some very good years, and there has been some dropoff,” Mets general manager Omar Minaya told the New York Daily News. “He still had 50 RBI in a part-time role last year. The key for him is playing time. I think he might be able to get more playing here as the year goes on.”

Carlos Silva, SP, Cubs: Injuries had a lot to do with his demise in Seattle. But his flagging confidence and irritable demeanor were even bigger concerns. Getting him into the right frame of mind to pitch will be no small challenge. He won just five games in two seasons in Seattle after winning 13 times for Minnesota in 2007.

“For me, when I get to spring training, I forget about everything,” he told the Chicago Sun-Times. “When you're in Seattle, in the clubhouse, around the coaches, the only thing they've got in their mind is the two bad years that I've had. But walking in here right now the only thing you hear is, 'Welcome to the Cubs' and 'Good luck for the season.' Nothing negative. This is going to be a new start.”

Oliver Perez, SP, Mets: He was spectacularly bad last season, owing, at least in part, to chronic knee problems that required surgery. But the former 15-game winner’s extreme wildness –which led to a 6.82 ERA – made you wonder if his head was OK.

He seemed to have a productive winter rehabbing his knee, so that’s a start. “I want to be healthy, because it’s not easy coming from surgery, and having been through that was very difficult; but it is what it is, I have to think positive for 2010, Perez told Noroeste, an online Mexican newspaper.