Francisco Liriano was signed by the San Francisco Giants as a free agent in 2000, from the Dominican Republic. Originally an outfielder, he moved to the mound after showing the Giants a mid-90s fastball. He made his North American debut in 2001, pitching 62 innings for the Arizona Rookie League Giants, posting a 3.63 ERA with a 67/24 K/BB and 51 hits allowed. He threw in the low-90s in rookie ball and showed a promising, if erratic, breaking ball. I gave him a Grade C in the 2002 STATS Minor League Scouting Notebook. I didn't have the space to write about many rookie ball guys back then, so the fact that he was mentioned in the book at all indicated that he was very intriguing. I mentioned that he had a very good arm, but needed time to refine his secondary pitches and command.
Liriano was assigned to Hagerstown in the Sally League in 2002. He made 16 starts, pitched 80 innings, posting a 3.49 ERA with an 85/31 K/BB and 61 hits allowed. He boosted his fastball into the 95 MPH range, and made huge strides with his slider and changeup, both looking like plus pitches. On the negative side, his command was inconsistent, and he missed half the season with a sore shoulder. I gave him a Grade B- in the 2003 Baseball Prospect Book, noting that he had excellent potential but that the shoulder issue was a significant red flag.
2003 was a lost season: he pitched just 11 innings all year due to more shoulder problems. He pitched well in instructional league, and the Twins traded for him as part of the A.J. Pierzynski deal that also brought Joe Nathan and Boof Boonser to Minnesota. I gave him a Grade C in the '04 book, writing that Liriano "has enormous potential if he's actually on the mound," but I was concerned enough about the health problems to limit his grade.
Liriano's shoulder didn't bother him in 2004. He posted a 4.00 ERA in 21 starts for High-A Fort Myers, with a 125/43 K/BB in 117 innings, then finished the year with seven strong outings in Double-A, with a 3.18 ERA and a 49/17 K/BB in 40 innings. His velocity fluctuated from 90 to 96 MPH, but his slider and changeup continued to advance. Command was still erratic, and there was still concern that he would break down physically. I gave him a Grade C+ in the '05 book, noting again that he had "a lot of potential" but warning that he could struggle with his control if rushed too fast.
Liriano began 2005 with Double-A New Britain. He got off to a somewhat slow start, but heated up as the season progressed. He made 13 starts for New Britain with a 3.64 ERA and a 92/26 K/BB in 77 innings. Promoted to Triple-A Rochester, he was totally dominant in the second half of the year, posting a 1.78 ERA with a 112/24 K/BB in 91 innings and a mere 56 hits allowed. Scouts reported sustained mid-90s heat, hitting 98 MPH at times. He continued to sharpen his secondary pitches, and his command took a huge leap forward in the second half. He led all of the minors in strikeouts. He posted a 5.71 ERA in 24 innings for the Twins late in the year, but with an excellent 33/7 K/BB. I gave him a straight Grade A in the 2006 book, writing that he could be another Johan Santana, and that I expected "good things if his health holds up." I rated him as the Number Two pitching prospect in baseball.
"Good things" was an understatement for 2006: he was amazing, going 12-3, 2.16, 2.55 FIP, with a 144/32 K/BB in 121 innings and just 89 hits allowed for the Twins, being used in relief early in the year until switching to the rotation. He was simply unhittable, with a blistering fastball, and, at times, the best slider I'd ever seen at the major league level. However, his arm finally gave out, and he had to have Tommy John surgery, missing all of 2007 on rehab.
As you know, Liriano's recovery wasn't as easy as it is for some TJ survivors. He spent much of 2008 in Triple-A, then suffered through a mediocre '09 season, looking like he was pitching rather tentatively at times. In 2010, however, he was back to something like his old self, going 14-10, 3.62 with a 201/58 K/BB in 192 innings for the Twins. The ERA was deceptive; his FIP was much better at 2.66, almost as good as 2006. His fastball, which was just in the 90-92 MPH range in '08 and '09, was back up to the mid-90s last year.
Liriano's potential was always apparent when he was in the minors, but issues with health and command made me rather cautious about his grades until the 2005 breakthrough. I find it interesting that, in the minors, it was the shoulder that bothered him much of the time, but that it was the elbow that eventually blew out. Will those shoulder problems recur? Or is he safely past the injury nexus? He is now 27. If he stays healthy, I don't see any reason to expect him to be less than excellent. But exactly how durable will he be?