Prior on the comeback trail

He's been one of the most exciting, tantalizing young pitchers of the past half-decade -- or at least at one point he was -- and year after year it seemed like no one could resist the annual "lottery ticket" that was picking Mark Prior.

Now that he's a San Diego Padre, will you still be fooled? In 2003, Prior was a 22-year-old 18-game winner with a 2.43 ERA and 245 strikeouts, and had what seemed like a certain Hall of Fame career ahead of him. He seemed destined for multiple Cy Young Awards, annual first-round fantasy selections and All-Star Game appearances. The shame of this story, though, is that since then, you probably couldn't find a more ideal poster boy for "injury-prone pitcher." Prior, who made 30 starts in that breakout 2003, has made a total of 57 since; that's an average of 14.3 per season. He didn't even pitch in 2007.

Let's consider it at least possible Prior won't pitch in 2008, either, because he's coming off major shoulder surgery performed April 24. At the time, Dr. James Andrews performed a debridement of the right-hander's rotator cuff, and repaired labral and capsular injuries. Prior said later in the season he planned a return in time for Opening Day, but all indications seem to be he'll miss a chunk of the season, maybe a month or two, maybe more. Until we get a sense of how his rehabilitation is going in the spring, the reality is that we won't know what his exact return date is. It's anyone's guess.

I'd probably approach Prior assuming he'll miss half the season, since it might be the All-Star break before he has any chance of recapturing his pre-injury form. One good thing: He picked the right place to attempt a comeback, signing a one-year deal with the Padres laced with incentives. A fly ball pitcher, Prior should be helped by Petco Park's spacious dimensions, especially accounting for the fact his velocity might be down initially upon his return. A more hittable Prior might mean a more homer-prone Prior, after all.

As for Prior's draft-day value, some might remember I wasn't fond of the rehabbing Pedro Martinez in 2007, knowing his prognosis about a year ago today had him out until at least June. I'd call Prior at least that much a risk. Martinez easily ranked outside of my top 50 starting pitchers, more of a late-round gamble to stash if your league used DL spots, which led a lot of owners to question my skepticism about him. Well, folks, prepare your similar questions about Prior, because I'd call him no better a bet than Martinez was entering 2007. He's not a guy to forget about entirely, but also not one I'd put any noticeable stock in at the draft table. Think final rounds, after your pitching core is set.

Royals sign Olivo

Well, the Royals just signed themselves a right-handed, light-hitting, strikeout-prone, weak-armed catcher. Sounds a lot like the guy they already had on the roster, doesn't it?

Miguel Olivo on Thursday joined the eerily similar John Buck as members of the Royals, signing a one-year deal with an option for 2009. Scary thoughts: Neither batted better than .237 in 2007. Neither has better than a .239 batting average or .705 OPS for his career. Both strike out more often than once every four at-bats, and neither is better than a .231/.685 hitter against right-handed pitching. In simulation baseball leagues, it's the kind of "platoon" best described in one word: nightmare.

In fantasy? It's not much better. The Royals would be smart to keep only one, and pair him with a stronger defender who can hit right-handers. Unfortunately, that's not likely to happen, so Buck and Olivo might duke it out for at-bats all season, in much the way Buck and Jason LaRue did in 2007. Barring one grabbing hold of the starting role in the spring, neither will be particularly attractive outside of No. 2 catcher status in AL-only formats. And even then, both would be batting average killers.

Erstad joins Astros

That groan you might have heard late Thursday night was the collective owners -- or prospective ones -- of Astros outfielders Michael Bourn, Hunter Pence and Carlos Lee. Perhaps first baseman Lance Berkman's owners, too, joined in the fray. That was the night Darin Erstad, one of the most overrated players of the past several years, signed a one-year, $1 million deal to do little more than steal at-bats from more interesting Astros.

Think about it: Who does Erstad most likely steal at-bats from? Bourn in center field is the most logical choice, but like Erstad, he's a left-handed hitter, so it's not an ideal platoon at all. Pence in right field is a possibility since he's a right-hander, except that the rookie batted .314 with an .872 OPS against right-handers, and doesn't need to be losing at-bats against that side to a player who finished significantly beneath his rates against that side in 2007. Berkman and Lee, meanwhile, are the centerpieces of the offense and unlikely to sit often.

The smart move for the Astros would be to make Erstad a little-used fourth or fifth outfielder or defensive replacement, especially since he hasn't registered an OPS better than .746 since that out-of-nowhere All-Star 2000 season of his. He's decent insurance in case Bourn doesn't pan out, but keep an eye on his role in the spring and hope it's not bigger than that. Erstad shouldn't play enough to warrant fantasy appeal, and even if he does, he's a weak bet as more than an NL-only fourth or fifth outfielder. Bottom line: You don't want this guy, and the Astros shouldn't in any significant role for 2008, either.

Tristan H. Cockcroft covers fantasy sports for ESPN.com. You can e-mail him here.