There are a number of regulars struggling at the plate for the Mariners, but of all those, perhaps the most surprising is Jack Cust. This was, after all, supposed to be the team's biggest offensive upgrade of the past winter.

Many of us thought the move made sense -- myself included.

But now, he's hitting .171 with a .511 on-base-plus-slugging percentage and zero home runs.

Nope, that won't work for a DH.

And unlike other struggling regulars like Chone Figgins and Miguel Olivo, his line drive percentage is down. Cust is at only 15.6 percent in line drives, compared to 21.8 percent last year, 19.8 percent in 2009 and 20.8 percent in 2008, not to mention a 21.4 percent average for his career.

So, while his batting average on balls in play is lower, it's not a slam dunk to attribute this to bad luck.

Cust is making contact at the same rate he was in the past. He's actually seeing more fastballs this season than in the past. And he isn't swinging at bad pitches more than he has in the past. Cust just isn't hitting the ball as hard as he has in past years when he makes contact. He isn't hitting as many line drives, nor as many homers. He's hitting far more grounders which he isn't built to leg out for hits and far fewer of the flyballs that tend to leave the yard.

And with a "true results" hitter, that's a problem.

Yes, it's a surprise. And at his age of 32, some of those "surprises" can signal the beginning of the end. We're not at the four-week mark of the season yet, so Cust will get more time to deliver.

The question is, how much longer?

Judging by recent history, not a whole lot.

Brad Wilkerson was signed to a similar one-year deal for similar money by the M's prior to 2008 to play right field.

One month into that season -- on April 29 to be exact -- Wilkerson played his final Mariners game at age 30. He was released with a .232 batting average and .652 OPS.

Fast forward to last year, when Ken Griffey Jr., 40, was floundering in the DH role. His final game as a regular player would be on May 11, when he was hitting .200 with a .489 OPS.

After that, he played sparingly and finally retired on June 2.

Now, in both cases, the Mariners entered the season under the impression they were trying to contend for something. There is no such urgency with this year's team.

Still, while that might buy Cust some time, teams can't keep running a black hole out there in the middle of the order. Especially when the peripheral numbers suggest the contact is the same as it was in the past, only not as powerful.

Cust has far worse hitting numbers than Wilkerson and is pretty much even with what Griffey produced. So, yeah, he's right in that DFA wheelhouse and at the age for it as well.

So, how much longer?

Well, we're told that Franklin Gutierrez should be ready to resume baseball activity. After that, it could take him a few weeks before he's ready to rejoin the club. There will have to be a roster move made at that time.

But still, even if Gutierrez doesn't return until June, I don't see Cust getting that long.

Not when you have Milton Bradley who can DH, as well as Adam Kennedy.

I'd say, at most, that Cust will get until mid-May before he loses his regular spot. After that, he can be used sporadically, then cut loose once Gutierrez is ready. And even mid-May seems a bit long to me since Cust is already sitting out more than a game a week these days. His situation is getting dire. He has to show the team he can turn this thing around soon.

This road trip would be a good place to start. Comerica Park is a good place for gap hitters to line their extra-base stuff (assuming they can still hit line drives). Fenway Park makes for a good place to pad -- or, in Cust's case, to start -- your home run stats.

The weather is a bit warmer out east these days as well. This is where General Cust will have to make his final stand.

If he doesn't, then all bets are off. The team will return home in early May and I'm thinking Cust will no longer be the everyday DH by mid-month.

His time in Seattle isn't over yet. But it's getting real late, real early for a hitter who has replacements looming.