Texas Rangers Diamond quickly rose through the
Rangers system, dominating the competition for
Spokane in the
Northwest League and
Clinton in the
Midwest League in 2004. In the fall of 2004, Diamond made a name for himself in an obscure Instructional League game during which he tripped and fell on the mound while attempting a
pickoff move. The opposing
Oakland A's prospects laughed at Diamond, who then walked off the mound towards the A's dugout and told them that the next person to laugh was going to be wearing a
fastball in the temple. Diamond then threw his next pitch three feet behind the hitter at the plate and then delivered nine consecutive strikes to punch out the side. In , Diamond was named the Texas Rangers
Nolan Ryan Minor League Pitcher of the Year in his first full professional season, splitting the campaign between Single-A Advanced
Bakersfield in the
California League and
Frisco in the Double-A
Texas League, combining to go 13–4 with a 3.53 ERA (59 ER/150.1 IP) and 169 strikeouts in 28 starts. He was ranked by Baseball America as the 3rd-best prospect in the Rangers system and the 4th-best prospect in the Texas League. Diamond returned to Frisco in where he led the Texas League in strikeouts, but struggled with control. During
spring training the following year, he experienced elbow soreness and was found to have a torn elbow ligament. He underwent
Tommy John surgery and missed the entire season while recuperating. Diamond struggled in with a 6.20 ERA in 12 games for Double-A Frisco.
Chicago Cubs On September 1, 2009, Diamond was designated for assignment by the Rangers, on September 4 the Cubs acquired him. On September 21, 2009, the Cubs designated him for assignment, making room for Tyler Colvin, never throwing a pitch for any team in the system. Diamond reported to the club's Mexicali team, replacing pitcher
Jeff Samardzija on the roster. On August 3, 2010, Diamond made his major league debut against the
Milwaukee Brewers. Diamond pitched 6 innings giving up 3 runs on 7 hits walking 3 and striking out 10 in a 4–3 loss to the Brewers. His 10 strikeouts tied Mark Prior for a franchise record for most strikeouts in a debut. He was released on June 15, 2011, after recording an 8.66 ERA in nine starts and five relief appearances with the Iowa Cubs.
Minnesota Twins The
Minnesota Twins signed Diamond to a minor league contract on June 20 and assigned him to Triple-A
Rochester. On July 23, he was released. ==Personal==