Professional career

Montreal Expos/Washington Nationals

Balester was drafted by the Montreal Expos in the fourth round of the 2004 Major League Baseball draft out of Huntington Beach High School. He was one of two high school players selected by the Expos in the 2004 Draft, with shortstop Ian Desmond being the other. After the draft, the Expos revealed that they hoped Balester could develop into a starting pitcher that would be in their rotation in three to five seasons. On July 10, Balester signed with the Expos and was assigned to the Rookie-level GCL Expos. In five games, he had a 1-2 win-loss record, a 2.19 ERA and a 1.014 WHIP.

Before the 2005 season, the Expos relocated to Washington and became the Washington Nationals. Baseball America also named Balester the 10th best prospect in the Nationals organization and listed him as having the best fastball of any minor leaguer in their system, which could be thrown at a maximum of 95 miles per hour. To begin the season, Balester joined the Class-A Savannah Sand Gnats and made his debut for the club on April 11, giving up just three hits in six innings and being awarded with the win. In a start against the Greensboro Grasshoppers on July 10, Balester allowed just one hit in eight innings of work, prompting Greensboro News & Record columnist Bill Hass to claim that, "The young right-hander turned the Hoppers hitters into traffic cones." On July 29, Baseball America mentioned Balester as a breakout player, along with infielder Kory Casto. In 24 games for Savannah, 23 of which were starts, he went 8-6 with a 3.67 ERA, and a 1.176 WHIP. After the season, Baseball America listed Balester as the second-best prospect in the Nationals system, behind third baseman Ryan Zimmerman.

Balester began the 2006 season with the High-A Potomac Nationals, where he got off to a bad start, going 1-3 with a 6.91 in nine starts. On the bad start, Balester said, "It kind of has been hard. I did so well last year. I think it's going to be good for me that I am failing a little bit more so that I know how to fail. I know I can use this in the future." He also added that, "I get way too high expectations for myself and I've got to realize I am only 19 years old." In late August, after going 4-5 with a 5.20 ERA and a 1.521 WHIP in 22 starts for Potomac, Balester was called up to Double-A Harrisburg. According to the Washington Times, Balester had already booked a flight home to Huntington Beach, expecting to not receive a call-up to Double-A. In three starts for Harrisburg, he went 1-0 with a 1.83 ERA.

In 2007, he was named the top prospect in the entire Nationals organization. Balester started the season with Harrisburg, where he finished the previous year. On July 7, Balester was named to the Team USA roster for the All-Star Futures Game at AT&T Park. A week after being named to the Futures Game roster, Balester was called up to the Triple-A Columbus Clippers. In 17 starts for Harrisburg, he went 2-7 with a 3.74 ERA and then in 10 starts for the Clippers, he went 2-3 with a 4.18 ERA. After the season, there were rumors that the Nationals could trade him to the Tampa Bay Rays, in exchange for outfielder Elijah Dukes.

Balester began the 2008 season with Columbus, going 9-3 with a 4.00 ERA in 15 starts for the club. He was called up from Triple-A Columbus on June 30, and made his debut the following day against the Florida Marlins. He pitched five innings, striking out three, and allowing one hit in a 9-6 Nationals win. With the win, he became the first Nationals starter to win his debut since Dan Smith did in 1999, when the team was still playing in Montreal. He started 14 more games for the Nationals, going 3-7 with a 5.51 ERA.

In Spring training 2009, Balester was part of a battle with Jordan Zimmermann and Shairon Martis for the final two spots in the Nationals rotation. However, he eventually lost the battle and was optioned to the Triple-A Syracuse Chiefs to begin the season. During Spring training, he went 1-1 with a 6.75 ERA, prompting Nationals manager Manny Acta to state that, "We need Collin to go down there and get some consistency on his command and three pitches. He took the news very well. He is going to go down there and work hard. I'm sure we are going to be seeing him this year and for years to come." On July 23, after Zimmermann was placed on the 15-day disabled list, Balester was called up to take his place in the rotation. On August 25, the Nationals signed Liván Hernández from free agency and to make room on the roster, optioned Balester to Triple-A. In seven starts for the Nationals in 2009, he went 1-4 with a 6.82 ERA. While with Syracuse, Balester strained a muscle on his left side, which ended his season. In 20 total starts with the Chiefs, he went 7-10 with a 4.44 ERA.

On March 15, 2010, Balester was sent to minor league training camp, ensuring that he would start the 2010 season in Syracuse. To start the season, Balester recorded an 11.65 ERA in five starts for the Chiefs, prompting the Nationals to send him to extended spring training in order for him to convert to being a relief pitcher. On July 24, Balester was called up by the Nationals to replace Luis Atilano, who had been placed on the disabled list. That day, he came into the game to replace J. D. Martin and hit Milwaukee Brewers second baseman Rickie Weeks in the head with a fastball. However, Weeks played the following day. Nine days later, Balester again hit a batter in the head, this time it was Arizona Diamondbacks third baseman Mark Reynolds. Much like Weeks, Reynolds was fine, but Balester still commented that, "You don't want to do that kind of stuff. It's the second time I did that, but it's one of those things you never want to have happen in your career. It's obviously unintentional. It's not a good situation to be in." On August 8, Balester was optioned back to Syracuse, only to be recalled on August 24, when Stephen Strasburg was placed on the disabled list. However, a day later, he was sent back down to Triple-A. Balester was recalled again for a third time on September 5. In 35 total games for Syracuse, he went 3-3 with a 5.87 ERA, while in 17 games for Washington, he went 0-1 with a 2.57 ERA.

In 2011, Balester was optioned again to Triple-A Syracuse to begin the season. On April 17, after throwing five scoreless innings for the Chiefs to begin the season, he was called up to replace Todd Coffey, who had been placed on the disabled list. He was optioned back to Syracuse on April 24, after making two appearances, allowing three runs. After Tom Gorzelanny was placed on the disabled list on May 28, Balester was recalled by the Nationals. At the time of his call-up, he had made 13 appearances with a 3.71 ERA and struck out 18 batters for Syracuse. He spent just one day with Washington as he was optioned back to Triple-A the next day without making an appearance, however, he was recalled again on June 15. He was designated for assignment on July 5. In eight games with the Nationals, he had a 4.61 ERA and a 1.683 WHIP. He was re-added to the 40-man roster on July 7, after the Nationals secured optional waivers for him, meaning they could take him off waivers, should a team try to claim him. On August 2, he was recalled by the Nationals, replacing Atahualpa Severino on the 25-man roster.

Detroit Tigers

On December 9, 2011, Washington traded Balester to the Detroit Tigers for Ryan Perry.

In 2012, Balester was on the opening roster for the Tigers for the first time in his career. However, he was designated for assignment by Detroit on May 23.

He was granted free agency on November 2.

Texas Rangers

Balester signed with the Texas Rangers on November 28. He was assigned to the Triple-A Round Rock Express to begin the 2013 season. He pitched in the rotation in April but after a start on April 30, he was placed on the disabled list the next day with an elbow issue. On June 6, Balester underwent Tommy John surgery, ending his season and delaying his start to 2014.

Pittsburgh Pirates

Balester signed a minor league deal with the Pittsburgh Pirates on November 20, 2013.

Cincinnati Reds

Balester was traded to the Cincinnati Reds on June 19, 2015. On August 23, 2015, Balester was promoted to the Reds. He elected free agency on November 4.

Samsung Lions

On December 18, 2015, Balester was signed by the Samsung Lions of the Korea Baseball Organization. He was released on May 18, 2016.

Personal

Balester and his wife, Ashley, have been married since 2009.

[ Source: Wikipedia ]