Rookie Review: Moises Sierra, OF, Toronto Blue Jays
The Toronto Blue Jays promoted outfield prospect Moises Sierra to the major leagues last week. He's off to a fast start, 6-for-13 (.462) with a double and two RBI in his first five games. This comes on the heels of a .289/.360/.472 performance for Triple-A Las Vegas, with 17 homers, 39 walks, and 86 strikeouts in 377 at-bats. Let's take a look at what the Blue Jays have here.
The Blue Jays signed Sierra out of the Dominican Republic in 2005. He was compared to a young Raul Mondesi due to his package of tools, but his bat was very raw. He was mediocre in the 2006 Dominican Summer League (.253/.345/.37), ineffective in the 2007 Appalachian League (.203/.248/.357), and nothing special in the 2008 Midwest League (.246/.297/.364 with 114 strikeouts and 26 walks). The tools were still there, though, and he began putting them together in 2009 when he hit .286/.360/.393 in the Florida State League, dramatically lowering his strikeout rate in the process.
2010 was lost to injuries (broken leg, sprained hand, strained oblique), but he was healthy in 2011 and finally tapped his natural talent more effectively, hitting .277/.342/.436 with 18 homers, 39 walks, and 93 strikeouts in 495 at-bats for Double-A New Hampshire.
His 2012 Triple-A performance benefits greatly from his home park: he hit .319/.391/.529 in Las Vegas, but just .254/.323/.405 on the road. Still, the Blue Jays see enough progress in him that they've moved him to the Show, and his emergence made it easier to trade Eric Thames and Travis Snider.
Sierra is 6-0, 225 pounds, a right-handed hitter and thrower, born September 24, 1988. His two best tools are his raw power and his throwing arm. He makes contact reasonably well and has made a lot of progress reducing his strikeouts, but remains impatient and I don't think he's a great bet to hit for high batting averages. It will also be interesting to see what happens when major league pitchers begin feeding him breaking balls. He runs well but is an ineffective basestealer. His throwing arm works well in right field, strong and usually accurate, but he lacks the range to play center on a regular basis.
I don't think Sierra will be as good as Mondesi was; Raul was already a strong major league hitter at this point in his career (.306/.333/.516 at age 23, .285/.328/.496 at age 24, OPS+123 both seasons) and was a much more significant threat on the bases. Sierra reminds me more of Jose Guillen, not a star by any means but a guy who had some productive seasons with the bat in his late 20s and early 30s.