Baseball’s Deepest Starting Rotations

As I wrote several months ago, the average team gets about 124 starts from the five guys slated as their rotation at the beginning of the season. That means that nearly one quarter of their games are started by a mid-season replacement, very often someone who wasn’t good enough to crack the rotation in March.

Logically enough, there’s been increased focus on each team’s sixth, seventh, and eighth starters—in many instances, the number six guy is nearly as important as a club’s number five. Certainly, if that guy is a prospect not quite ready for the rotation—think Francisco Liriano or Jered Weaver last year, or Philip Hughes or Homer Bailey this season—he can end up contributing as much as anyone else on the club.

With that in mind, let’s look at the five deepest pitching staffs in baseball this year. For the purpose of this unscientific ranking, I’ve all but ignored the quality of the starting five. Instead, I look at the guys likely to fill in, whether they’re ready right now (like, say, Jeff Karstens or Carlos Villanueva) or are expected to be ready at some point during the season (Tim Lincecum, perhaps).

5. Arizona Diamondbacks

If I were ranking teams based on the number of possible rotation replacements, the D-Backs might be at the top of this list. Once Randy Johnson is healthy, there’s only one spot for Dana Eveland, Edgar Gonzalez, Enrique Gonzalez, Dustin Nippert, and Micah Owings, all of whom are still in big-league camp.

Beyond that, Evan MacLane (who was sent down earlier this week) will remain in an option in Triple-A, and Juan Cruz, likely a member of the Arizona bullpen, is always a possibility to plug into the rotation. For 2007, none of those pitchers have particularly high upside, but three or four of them will probably be better than what the Giants get from their fifth spot in the first half.

4. Toronto Blue Jays

The Jays are the American League equivalent of the Diamondbacks, with just as many fifth starter options and quite possibly even more use for them. Having brought in John Thomson, Victor Zambrano, and Tomo Ohka, Toronto may have limited opportunities for its younger starters, but when some of those guys get hurt, or if Gustavo Chacin is ineffective, there’ll be a Triple-A rotation full of options.

In fact, the number of possible replacements boggles the mind. Just looking at pitchers who got multiple big-league starts last year, that includes Casey Janssen, Shaun Marcum, Josh Towers, Scott Downs, Ty Taubenheim, and Dustin McGowan. Some of those guys will battle for bullpen slots as well, but that’s a very solid Syracuse rotation, if it comes to that. Janssen and Marcum each had a big-league ERA+ of 93, while Taubenheim’s was 96. As with Arizona, there’s isn’t a ton of short-term upside here, but short-term depth they got.

3. Los Angeles Dodgers

The competition for the Dodgers number five spot is officially down to three: Mark Hendrickson, Hong-Chih Kuo, and Brett Tomko. That already leaves Chad Billingsley outside looking in, moved to the bullpen for the time being. As long as that move isn’t forever, the Dodgers could have two of the better replacement starters in the game.

In about 30 innings of each last year, Kuo was much better as a starter: racking up a 3.07 ERA in that role against a 5.34 mark as a reliever. Billingsley was nearly as good in his 16 starts, keeping his ERA well under 4.00. In addition to those two pitchers, one of Tomko or Hendrickson will constitute insurance, while having Elmer Dessens in the bullpen offers one more emergency solution. Looking further ahead, top prospect Scott Elbert could make himself a factor by season’s end, as well.

2. Milwaukee Brewers

While it isn’t written in stone, the Brewers rotation is all but established: Claudio Vargas will grab the number five spot, making it likely that Carlos Villanueva will head back to Nashville. Villanueva leads a group of Nashville starters that includes Zach Jackson, Tim Dillard, and Yovani Gallardo, any one of whom could be a capable rotation fill-in at some point during the 2007 campaign.

While neither Villanueva nor Jackson (nor Dillard or Ben Hendrickson, for that matter) has a very high ceiling, either would probably be a capable MLB fifth starter right now. In six starts last year, Villanueva managed a 3.69 ERA with a nearly 4/1 strikeout-to-walk ratio. Jackson wasn’t so successful, but performed above replacement level in his seven starts. Gallardo is the most exciting of the bunch: he probably won’t be ready until the all-star break, but is one of the top pitching prospects in the game.

1. Minnesota Twins

I was torn about where to put the Twins on the list: is it right to say that your rotation is deep if you sign bad pitchers to displace good ones? That’s essentially what Terry Ryan has done, virtually guaranteeing Ramon Ortiz a starting job at the expense of an opportunity for Matt Garza or Glen Perkins. If you work hard enough, you can find the logic in that move, but it’s a stretch, as I wrote last month.

As it stands now, the rotation is likely to include Ortiz, Carlos Silva, Boof Bonser, and Johan Santana. If Sidney Ponson somehow lies, cheats, or steals his way into the fifth spot, Rochester’s numbers two through five could well be better than Minnesota’s. ZiPS forecasts Garza, Scott Baker, and Kevin Slowey to post ERAs under 4.50 this year (better, incidentally, than Silva, Ortiz, Bonser, or Ponson), and even projects forgotten man J.D. Durbin at 4.86.

Even if all the right people got jobs in the opening day starting rotation, the Twins would still have plenty of options; I just wish they had realized that before wasting all those innings on Ponson and Ortiz.

Honorable Mention

The team that came closest to making the cut was the Angels. With Bartolo Colon and Jered Weaver both on the shelf, their depth is already being tested. Beyond youngsters Joe Saunders and Dustin Moseley, they have a couple of useful swingmen in their pen in Hector Carrasco and Darren Oliver.

The other club on the fringes of this debate is the New York Yankees. If Carl Pavano is healthy and holds on to his rotation spot, that makes Jeff Karstens number six, with Philip Hughes right at his heels. Humberto Sanchez may not be of Hughes’s caliber, but if he gets over his current forearm problems, he could be a solid option before the season is out.