Is Adam Dunn in a slump or washed up?

Adam Dunn is only 31 years old and he's been one of the most consistent players in recent years, hitting 40 home runs four seasons in a row and then 38 the past two.

He's not going to get there this year. He's hitting .176 with five home runs. He's still drawing his walks and striking out a ton -- tied with Drew Stubbs for the major league lead. Eric Karabell does a good of breaking down Dunn's season here, including his 1-for-42 mark against lefties (and that one hit was an infield single).

White Sox chairman Jerry Reinsdorf says Dunn's struggles are just a matter of confidence, although somehow I doubt a player with 359 career home runs is lacking in confidence. No, it could be another answer. Maybe Dunn is just washed up. He fits the profile of the kind of player who can lose it in a hurry: big, slow, lacking in defensive skills. A few examples of that type:

Greg Luzinski: He averaged 32 home runs per season from ages 24 to 27, twice finishing second in the NL MVP vote. But he slugged over .500 just once more and his final season came at age 33.

Rocky Colavito: Through age 31, he had 328 home runs. He hit 30 at age 32, but his average slipped to .238 and he was never again a regular, finishing his career with 374 home runs.

Alvin Davis: One of the AL's best hitters with Seattle in the mid- and late-'80s, Davis was a slow first baseman with a great eye (although not as much power as Dunn). In 1989, at age 28, he ranked second in the AL in OPS. By age 31, he was done.

Pat Burrell: Like Dunn, he's a low-average power hitter who draws a lot of walks. He signed with Tampa Bay in 2009 at age 32 and hit .221 and was released early in 2010. A move back to the NL offered hope that he wasn't completely washed up. Maybe Dunn is undergoing the same problem of playing in the tougher league.

Richie Sexson: Topped 30 home runs six times through age 31, hit .205 at 32 and was cut loose at age 33.

Jeff Burroughs: The AL MVP with the Rangers in 1974, his last really good season came at 27 and by 31 he was a part-time DH with the A's.

Dale Murphy: A far better athlete than Dunn, but a big man who had a great age-31 season in 1987 and then lost it, hitting .228 in 1988 and never regained his previous skills.

Anyway, obviously I nitpicked a few examples, but just some food for thought. It should be noted that Dunn has a career strikeout/walk ratio of 1.67, but last had a career-worst 2.58 (that's 2.58 K's for every walk). He's a little better this -- 2.22 -- but that's still the second-worst figure of his career and his striking out a career-worst 34.9 percent of the time.

I don't think Dunn is this bad, but he's a pretty rare player in baseball annals, as there have been few players of his height and size. Is he done? It's too early to say that. Will he be worth the $56 million contract the White Sox gave him? I have some doubts.