Jon Lester will make his Chicago Cubs debut against the St. Louis Cardinals tonight. He signed six-year, $155,000,000 contact with the Northsiders this past winter so all eyes are on him. Our brief around here is prospects, so let's take a look at how Jon Lester ranked when he was a youngster.
Jon Lester was drafted by the Red Sox in the second round of the 2002 draft, out of high school in Puyallup, Washington. He was considered a first-round talent, but a scholarship to Arizona State put his demands in question and scared teams off. The Red Sox didn't have a first-round pick that year, so they found the money to sign Lester, although he signed late and pitched in just one rookie ball game.
He was considered a classic projectable lefty, throwing anywhere from 86 to 93 in high school but with a good chance to make that velocity more consistent with maturity. HIs breaking stuff was also promising but erratic. He earned a Grade C+ in the 2003 book, noting that he could develop into Mark Mulder but could also turn into Dan Serafini.
Lester spent 2003 in the Low-A South Atlantic League, going 6-9, 3.65 with a 71/44 K/BB in 106 innings. His component ratios were mediocre. He boosted his velocity consistency a tad to 88-92, and showed a better changeup, however his curveball and slider were still considered very erratic. He got a Grade C+ again, noting his long-term promise but pointing out the mediocre (at that time) component ratios. He was a high-ceiling talent but there were a lot of unanswered questions.
2004 was a mixed season. On the good side, he boosted his velocity again, to 89-93, high 95. His curve improved. He went 7-6, 4.28 with a 97/37 K/BB in 90 innings for Sarasota in the Florida State League, showing better components. He also missed three weeks of pitching with a sore shoulder. I moved him up to Grade B in the 2005 book, worried about the shoulder but liking the better velocity and stronger K/IP ratio. He looked like he could be a number one starter, potentially, if his command sharpened a bit more and if he stayed healthy.
Lester stayed healthy in 2005, going 11-6, 2.61 with a 163/57 K/BB in 148 innings in Double-A, making a very successful transition to the high minors. His secondary pitches continued to improve, his velocity continued to bump up gradually, and he was dominant at times in the Eastern League. I gave him a Grade B+ and wrote that "there is every reason to think that Lester will be a successful major league pitcher."
Lester split 2006 between Triple-A and the majors, pitching brilliantly at times but with league-average results overall, which was still very credible for a 22 year old rookie in the American League East. Then he had the bout with cancer, non-Hodgkin lymphoma, but came back in 2007 and again posted league-average results in 63 innings.
The big breakthrough came in 2008: 16-6, 3.21 ERA, 144 ERA+, 152/66 K/BB in 210 innings, 5.0 WAR. He threw a no-hitter against the Kansas City Royals on May 19th. As you know, he's been one of the top starters in baseball ever since. His only bad year was 2012, and even that year he ran up 3.1 WAR.
As a prospect, Lester was a textbook case of a projectable young pitcher who gained strength, boosted his velocity, polished his secondary pitches and sharpened his command in a steady, nearly linear way. It seldom happens this smoothly and Lester did it despite his bout with cancer.