Major League Debuts as a Starting Pitcher

Hey, look at that, it's been a week again since I last posted. Oops. During the past week, major league active rosters expanded from a limit of 25 to a limit of 40. There are a few different general types of September call-ups: major league veterans who have spent the season at AAA, fringe major league players who get called up to give the big club more flexibility in games, guys who have no business being on a major league roster except for being great at one of the five tools (usually speed), or young prospects.

In the first three days of September, twenty-two call-ups made their major league debuts. Take a gander at the list:

• Matt Antonelli, 2B, SDP
• Wilkin Castillo, C, CIN
• Phil Coke, LHP, NYY
  
• Luis Cruz, SS, PIT
• Alcides Escobar, SS, MIL
  
• Dexter Fowler, CF, COL
• Mat Gamel, 3B, MIL
• Greg Golson, CF, PHI
  
• Mike Hinckley, LHP, WSN
• Wade LeBlanc, LHP, SDP
  
• Casey McGehee, 3B, CHC
• Jim Miller, RHP, BAL
• Jason Motte, RHP, STL
  
• Brad Nelson, 1B, MIL
• Jonathon Niese, LHP, NYM
• Josh Outman, LHP, OAK
• Jason Pridie, CF, MIN
  
• Rich Rundles, LHP, CLE
• Angel Salome, C, MIL
  
• Justin Thomas, LHP, SEA
  
• Luis Valbuena, 2B, SEA
• Josh Whitesell, 1B, ARI

I think Outman is a good last name for a pitcher. Anyway, as minor league playoffs end and a second, smaller wave of call-ups makes it to the big leagues, this list will grow a little more. I really want to focus on two debutants, though: Wade LeBlanc and Jonathon Niese. Those two recently became part of a large group that's still rather small in the grand scheme of baseball history. I'm talking about pitchers making their major league debut by starting a game.

Since 1956, 4439 different players have pitched in a major league game. Of those, 1270 (28.6%) debuted as a starting pitcher. So far in 2008, thirty-four different pitchers have made their debut as a starter. Usually, unless the pitcher in question is a mega-prospect known around baseball, fans of a team going up against one of these rookie pitchers figure the guy should get roughed up in his first start. After all, the thinking goes, he might have pitched well in AAA or AA, but he's in the majors.

It turns out that guys making their debut do tend to get roughed up more than the average pitcher making a start. This makes sense when you consider the guys who get called up, get shelled, and get sent back to the minors shortly after. This is also probably most of the reason why fans figure almost any debuting pitcher should get lit up on the mound.

I've put together a chart showing the combined ERA of all starters making their debut in a given season against the ERA of all major league starters in that season.


(click image to enlarge in a new window)

Unsurprisingly, most of the time the rookies allow more earned runs. Interestingly, however, there are a few seasons where they actually had a lower ERA than the average starter. The most recent time that happened was in 2005 when guys like Paul Maholm, Kyle Davies, Dustin McGowan, and J.P. Howell had great debuts. Sure there were clunkers, too, like Sean Henn and Ervin Santana's first games, but they were more than balanced by good games that year.

The prior season was the worst since 1956 for debuting starters. Thirty-four starters combined to put up an awful 7.68 ERA and an abysmal .990 OPS against. There were eleven starts with a game score of 30 or below, including one of -7 (belonging to Arnie Munoz). Ten guys couldn't even get through the fourth inning. It wasn't all bad: Chris Saenz, Daniel Cabrera, and Tyler Yates (great combo) each went six scoreless while Scott Kazmir, Chris Young, and Zack Greinke, among others, performed capably. All in all, however, it wasn't a great year for the newbies.

For fun, I decided to look at the numbers since 1998, the final round of expansion. In the past almost eleven seasons, 387 different pitchers have made their debut as a starter. In their debuts, they combined for the following pitching line:
1991.7 IP, 2093 H, 1265 R, 1175 ER, 934 BB, 1368 K, 309 HR, Average Game Score: 46

In the more familiar rate stats, that all turns out to be:
5.31 ERA, 1.52 WHIP, 6.18 K/9, 4.22 BB/9, 1.40 HR/9, .271/.354/.464 opponent batting line

It turns out there are a couple individual pitchers who put up similar numbers during the period between 1998 and 2008. The closest comparisons to all the rookies mashed together are these two:

• Rocky Biddle, 378.2 IP between 2000 and 2004:
  5.47 ERA, 1.53 WHIP, 6.20 K/9, 4.04 BB/9, 1.40 HR/9, .274/.357/.462
• Victor Santos, 602.1 IP between 2001 and 2007:
  5.21 ERA, 1.58 WHIP, 6.35 K/9, 4.17 BB/9, 1.29 HR/9, .284/.362/.467
  

Rocky Biddle is spot on. Besides Biddle and Santos, Jason Hammel and Paul Rigdon are also kind of close, Allen Levrault was a few strikeouts away from the group, and if you toss out Bill Pulsipher's first season, he's in the mix, too. Or, if you're a normal baseball fan: one current fringe guy, two forgotten guys and an ex-top prospect join the three listed above.

If you're curious about the actual year-to-year numbers or just want to see how your favorite starter(s) debuted, check out the Google spreadsheet I made listing all 1270 debuts as a starting pitcher since 1956.

EDIT: Of course, I post this and James Parr of the Braves debuts the next night with six scoreless innings against the Nationals. The Nats countered with rookie Shairon Martis, who went five innings while allowing two runs.