At the time he was traded for Michael Pineda, the reviews on Jesus Montero were mostly positive.
Jim Bowden had this to say:
Montero should develop into the Mariners' everyday catcher with designated hitter being an unfortunate option if catching does not work. Montero has a huge frame and is going to hit with power. He has a strong arm behind the plate but a slow release. He still needs help with footwork and calling a game, but his bat will play, and in time he should become adequate behind the plate. He has great bat speed, a smooth path to the ball and consistent sweet-spot contact. Montero should become a .300 hitter with 20-25 HR power in the major leagues.
Keith Law had this to say:
Law estimated that Montero has the potential to eventually hit 25-30 home runs a year, a number Law thinks would be even higher if Montero were to play in a park that isn't as hard on right-handed hitters. "If this guy can't hit for power in Safeco, then I don't know if there is a right-handed-hitting prospect who is going to hit for power in Safeco," Law said. While Law thinks Montero may not reach his full power potential right away, he said Montero's "advanced approach at the plate" should translate into a high on-base percentage right away.
Fast forward to May 23rd, and the former can't-miss prospect finds himself in his vehicle driving down Interstate 5 on his way to the Tacoma Rainiers where he will spend some time as a DH and a first baseman and put an end to his catching days. He goes down to Triple-A with .258 career batting average and just a .699 OPS in 732 career plate appearances. Where did it all go wrong?
Jesus Montero's preseason player profile had this to say about the young "catcher":
Montero's final 2012 numbers didn't knock anyone's socks off, but he held his own for the most part as a rookie. He had two primary liabilities at the plate: he struggled against right-handed pitchers (.609 OPS) and he struggled at home (.605 OPS). The latter problem could be taken care of by moving in the Safeco Field fences this year as many of his left-center drives should now fly away, or at least not turn into warning-track outs. The former problem is another story. Montero could not lay off the low-and-away junk righties offered last season, chasing way too often out of the zone. Until he fixes that issue, right-handed pitchers will continue to give him trouble.
In terms of hitting right-handed pitching, Montero actually did that better than he did lefties this season. In 76 plate appearances, Montero hit .225 but had an anemic .615 OPS while striking out 16 times. He hit three home runs, including a 441-foot monster home run off Brad Peacock, but many of his batted balls were either singles or routine flyballs. Montero has a rather unique natural swing as his nitro zone tends to be toward the right-center field gap. In reviewing his batted flyballs, he hit just two of them to left field while everything else went to center field and the other way. When Montero faced lefties, he hit just .167 with a .531 OPS. He had just 10 flyballs against lefties, and only one even challenged the warning track.
Montero's hitting was also better at home than it was on the road. He hit .220 at Safeco with a .670 OPS and just .200 with a .534 OPS on the road. In all, Montero had just five extra-base hits in 110 plate appearances. Some thought that his struggles behind the plate may have affected his numbers at the plate but the splits, albeit in a small sample size, do not play that out. When Montero caught, his career slash line is .281/.325/.447 in 348 plate appearances. Montero had a slash line of just .240/.284/.353 in 380 career plate appearances as a designated hitter.
The strange thing is the league is not pitching him terribly different this season from last year. They are throwing him more fastballs this season, but the frequency of where they are located is essentially the same yet he is doing worse with them. Here are the plate appearance results for Montero against fastballs in 2012 versus 2013: