Impact Index: No Tom Foolery

It’s baseball season and it’s Monday. When those two things get together, you get the Impact Index.

Impact Index is a new weekly post where we highlight the efforts of baseball’s unsung heroes. The bench guys. The bullpen arms. The twenty-third, twenty-fourth, and twenty-fifth men on their team’s roster. The players who typically enter a game in the late innings, when the outcome of the game hangs in the balance.

Every Monday we’ll bring you the stories of a bench guy or reliever, or two, who had a significant impact on his team’s games during the prior week. Sometimes the impact will be positive. Sometimes it will be negative. But it will always be critical to the outcome of the game.

If you are inclined toward sabermetric things, you’re no doubt familiar with the concepts of Win Probability Added, or WPA, and Leverage Index. If you think WPA stands for the World Pool-Billiard Association, then a little background information is in order.

WPA measures how a player affects his team’s Win Expectancy on a play-by-play basis. Win Expectancy is the percent chance a team will win based on score, inning, outs, runners on base and the run environment. It is calculated using data from every baseball game for which play-by-play information is available. Leverage Index measures how important a particular situation is in a game, factoring in the inning, score, outs and number of players on base. The Leverage Index is highest in the later innings, with the score tied or close, and runners on base.

We’ll be charting WPA and Leverage Index numbers throughout the week. But the player we highlight in the Impact Index won’t necessarily be the utility guy or relief pitcher with the highest cumulative WPA over the past six or seven games. If you want that information, you can find it on the leader boards on Baseball Reference or FanGraphs.

We’re about the story behind the stats. Who are these utility players and middle relievers? Where have they been on their baseball journeys? How did they end up in a position to decide the outcome of a game? And what happened once they got there?

This week’s Impact Index player is Tom Wilhelmsen, a relief pitcher for the Seattle Mariners. Wilhelmsen took a circuitous route to his first major league appearance last season, at the age of 27.

The Milwaukee Brewers drafted Wilhemsen, a Tucson, Arizona high school senior, in 2002 and he pitched for the Brewers in rookie ball and in Single-A in 2003. But after Wilhemsen twice tested positive for marijuana, the Brewers suspended him for a year.

Instead of focusing on baseball, though, Wilhemsen spent that year bartending in Tuscon hiking around the southwest. His year off from baseball turned into two years, and then three years, and before he knew it, Wilhemsen was completely out of the game. He got married, backpacked around Europe, and returned to tending bar in Tucson.

By 2009, he’d had enough of getting home at 4 a.m., smelling like beer. He’d kept in touch with this agent, who arranged for a tryout with the Mariners. Jack Zduriencik, the Mariners general manager, had been the Brewers scouting director when Milwaukee drafted Wilhelmsen. Zduriencik liked what he saw and signed Wilhelmsen to a minor-league contract. He pitched for the Mariners in Arizona Fall League and on their Single-A and Double-A squads in 2010.

Wilhelmsen debuted with the Mariners on April 3, 2011, throwing a scoreless inning in relief against the Oakland A’s. But it was rough going after that outing. In April and May, he tossed 9 2/3 innings in relief, giving up eleven hits and six earned runs, for a 5.19 ERA. The Mariners sent him back to Double-A and recalled him in August, to much better results. Over the last six weeks of the season, Wilhemsen threw 23 innings, giving up only fourteen hits and six earned runs, for a 2.31 ERA.

Fast forward to 2012. The Mariners opened their season on the road – in Tokyo, Japan– with a two-game series against the A’s. The teams then traveled back to the States, returned to spring training, and finished their series with two games this weekend in Oakland. Wilhemsen pitched in three out of the four games, all three victories for the Mariners.

In the first game, on March 28, Mariners ace Felix Hernandez held the A’s to one run through eight innings, but the Mariners had only mustered one run off A’s pitching. Wilhemsen came into pitch the bottom of the ninth, retiring the A’s in order on just nine pitches. He was back on the mound in the bottom of the tenth, the score still tied 1-1. The lead off hitter, Brandon Allen, reached on an error, but pinch runner Colin Cowgill was caught stealing. Wilhelmsen set the next two batters down in order. Two innings, no hits, no walks, and no runs. The Mariners scored twice in the top of the eleventh inning, making Wilhelmsen the winning pitcher.

Wilhemsen has two main pitches: a 95-mph fastball that he throws about 65 percent of the time, and a 78-mph curve ball. He used both to great effect inTokyo. Take a look:

Wilhemsen didn’t fare quite as well his next outing, on Friday night, April 6. The Mariners took 7-2 lead into the eighth inning. He gave up three singles, but allowed only one run to score when he struck out the final two batters, stranding runners on first and third.

In the final game of the series, on Saturday night, Mariners manager Eric Wedge again sent Wilhemsen to the mound in the eighth inning, this time with Seattle clinging to n 8-7 lead. The A’s had drawn to within a single run in the prior inning when Yoenis Cepedes hit a monstrous three-run home run. It was up to Wilhemsen to hold the line, and he did, retiring the side in order on a pop up, fly ball and strikeout. The Mariners held on for the victory.

Tom Wilhelmsen: from high school pitching star to Deadhead to bartender to major league pitcher. He’s our Impact Index player of the week.