Herrera, 22, has recorded only eight hits in 37 at-bats (.216 average) over his last 10 games at High-A Modesto.

Herrera hasn't shown any notable progress in his repeat season at Modesto. He's slashing just .235/.305/.360 and hasn't shown any increased proficiency on the bases, going 3-for-6 on his attempts. The center fielder seems to be losing some luster as a prospect and might only retain relevance in the deepest of dynasty formats at this point.

Herrera, 22, is batting .216/.281/.373 over 57 plate appearances at High-A Modesto.

Herrera struggled mightily with Modesto in 2013, and his second go-around at the High-A level doesn't appear to be going much better. He's seen his strikeout rate rise to 24.6 percent thus far, and while his .157 ISO is promising, Herrera still isn't producing nearly enough offense relative to the hitter-friendly environment in which he plays. The Rockies switched Herrera from the infield to the outfield over the winter in order to aid his ascent through the system, but his inability to find success at the plate in the California League is beginning to cast doubt on his chances of becoming a big-league player.

Herrera was optioned to the minors over the weekend, MLB.com's Thomas Harding reports.

The switch-hitting Herrera is transitioning to center field in 2015 after playing primarily at shortstop and third base throughout his minor-league career. The 22-year-old draws raves for his bounty of tools, which allowed him to put up 16 homers, 21 steals, and a .343 batting average for Low-A Asheville in 2013. However, he backslid at High-A Modesto last season to the tune of a .244/.302/.335 line, though a wrist injury bears some of the responsibility for his decline. He's likely on track for a repeat campaign in the California League.

Herrera was moved from shortstop to center field in the Rockies' fall instructional program and is expected to play at the new position in 2015, MLB.com's Thomas Harding reports.

Due to the presence of Troy Tulowitzki at the major league level as well as the Rockies' sizable crop of middle infield prospects that includes luminaries such as Trevor Story and 2014 draft pick Forrest Wall, Herrera will transition to the outfield in an attempt to aid his rise through the system. The 22-year-old switch-hitter lost a bit of luster after posting a .302 on-base percentage while showing a steep decline in slugging at High-A Modesto last season, but a nagging wrist injury likely had much to do with the downturn in performance. The speedy, lanky (6-foot-3, 190 lbs.) Herrera should make a relatively smooth move to the outfield in what figures to be a repeat season at High-A. If health permits, it shouldn't be long before scouts salivating over his toolsy skill set once again.

Herrera hasn't played in a game at High-A Modesto since Aug. 13 and is on the 7-day DL with an undisclosed injury.

With the minor league season coming to a close, it's possible we've seen the last of Herrera for 2014. Much like fellow Rockies shortstop prospect Trevor Story a year earlier, Herrera has seen his stock tumble with the move from the Sally League to Modesto. In his injury-plagued season, Herrera slashed a meager .244/.302/.335 over 72 games, with only four homers and a 9-for-16 success rate on the base paths.

Rockies prospect shortstop Rosell Herrera went 3-for-3 with a home run and two walks for High-A Modesto on Wednesday.

Herrera has gone ice cold since mid-June, hitting .229/.309/.351 over 34 games, striking out 25 times. Despite the concerns that he will need to move to third base full time, Herrera is still playing shortstop about 60 percent of the time.

Rockies shortstop prospect Rossell Herrera went 2-for-5 with two home runs for High-A Modesto on Wednesday, raising his season line to .313/.347/.393.

Herrera missed nearly six weeks with a sore wrist, and has been on fire since his return, hitting .400/.455/.600 with two doubles and two home runs in 10 games. He is likely to move to third base due to Troy Tulowitzki, though the emergence of Nolan Arenado could be an issue. In his last two games, he has one single, two doubles, and two home runs.