Of the quartet, Sosa has the highest ceiling thanks to a fastball that tops out around 95 mph. He also features a curveball and change-up in his repertoire. Sosa missed the first two months of the 2008 season after undergoing off-season knee surgery. He then headed to High-A ball – where he also made 14 starts in 2007 – and posted a 3.59 FIP with 62 hits allowed in 56.1 innings. In total, in 120 High-A ball innings in the last two seasons, Sosa has allowed 128 hits, in part due to his developing command. The 23-year-old showed improvements in his control by dropping his walk ratio from 5.09 BB/9 in 2007 to 2.88 BB/9 in 2008. His strikeout rate, though, also took a hit from 11.03 K/9 to 9.27 K/9. Sosa will begin 2009 in Double-A, which will be a great test for him and will help to determine if his secondary pitches will show enough improvement for him to remain in the starting rotation.
Martinez was originally signed by the Giants after being selected in the 12th round of the 2005 amateur draft out of Boston College. Despite spending four years in college, Martinez has moved through the system one step at a time, despite solid numbers in the low minors. Those stats included a 15-5 record in A-ball in 2006 and ratios of 1.99 BB/9 and 8.35 K/9 in 2007 at High-A ball. Part of the reason for the slow ascent is that Martinez’ stuff does not match up with his results. Although he posted a 3.09 FIP in Double-A in 2008, his strikeout rate plummeted to just 6.81 K/9, while his walk rate rose slightly to 2.25. The right-hander relies on solid command of his 88-91 mph fastball, curveball and change-up. Martinez is likely a reliever in the long run, thanks to a three-year drop in K-BB ratio from 5.19 to 4.19 to 3.03.
Joaquin, like Sosa, can dial his fastball up into the mid-90s and backs that up with a plus slider. His change-up, though, is lacking as a third pitch and he spent more time in the bullpen in 2008 than in the past. Joaquin spent the majority of the season in A-ball where he allowed 49 hits in 52 innings and posted rates of 5.12 BB/9 and 10.71 K/9. He also made nine appearances, including four starts, in High-A ball and posted a 3.87 FIP with 20 hits allowed in 19.1 innings. Joaquin should return to High-A in 2009 and spend much of the season working on his command and control.
English is the lone southpaw in the bunch. After an injury-plagued 2007 season, the 24-year-old is looking to make up for lost time and he had a nice season in 2008. In High-A ball, English posted a 3.62 FIP and allowed 121 hits in 135.1 innings. He also posted rates of 3.39 BB/9 and 8.98 K/9. The left-hander gets by with craftiness and deception, as his fastball does not exceed 88 mph. He also has a plus change-up, as well as a developing breaking ball. English could stand to induce a few more ground balls, but he has the makings of a solid No. 4 or 5 starter if he can tighten up his control.