Peter O’Brien is one of the more interesting prospects in the D-backs farm system. At the age of 25, he has logged just 10 at-bats in the show with one home run. Despite being a tremendous power threat, he's had issues finding a defensive home on the diamond. On the plus side, O’Brien has never had trouble hitting. He mashed 48 homers in his college career prior to the Yankees drafting him in 2012 with the 94th pick overall. In 2012, he made his professional debut and hit 10 HR, then went on to hit 22 in 2013, 34 the following year, and 26 last season.
Over four minor league seasons, O'Brien knocked 122 extra base hits while posting a career .273 average. While the hitting aspect of his game has come easy, his biggest issue has been finding a position where he can play significant time. While with the Yankees, O’Brien had much more flexibility due to the fact that he could play C, 1B, 3B, and the outfield. O'Brien saw time at all 4 positions while with the Yankees and earned an Arizona Fall League invite in 2013 to polish his skills. This allowed the Diamondbacks to get a very good look at him in their own backyard.
During the 2014 trade deadline, the Yankees sent him over to the Diamondbacks in exchange for Martin Prado. Later that year, Miguel Montero was traded to the Cubs and many speculated that O'Brien was the heir apparent to the starting catching job for the 2015 season. O'Brien received another invite in 2014 to the prestigious Arizona Fall League, but primarily saw time at the cold corner. With the outfield viewed as a position of need for the D-Backs at the time, this seemed like an odd developmental move considering Paul Goldschmidt had first base locked down. A secondary plan had O'Brien competing with Jake Lamb for the third base job in the spring of 2015.
A short time after the Montero trade, the snakes selected catcher Oscar Hernandez with their Rule 5 selection from Tampa. In addition, they signed Yasmany Tomas out of Cuba to battle with Lamb at third. The brakes were put on with Peter O'Brien and his developmental game plan changed. The D-Backs also acquired C Gerald Laird and moved minor league farm hand/backup catcher Tuffy Gosewisch to the top of the depth chart. This created an even larger log jam behind the dish than originally anticipated going into the 2015 season.
Arizona went into Spring Training last year with lofty hopes of a lot of young talent filling holes. They were hoping Jake Lamb, Oscar Hernandez, Archie Bradley, Chris Owings, and others could hit the ground running. However, Tuffy won the everyday catching job, Laird was named the backup and Hernandez went to the DL with a broken hand. The D-backs then announced that O'Brien would move to the outfield in the minors in 2015. This seemed peculiar but, O'Brien listened and still did not get the call. As the season wore on, Gosewich tore his ACL, Laird injured his back, and the D-backs still did not turn to Peter O'Brien. This was primarily because he was only playing outfield, but theoretically he could have switched back.
In July of 2015, The D-backs pulled off a trade to acquire Welington Castillo and then acquired Jarrod Saltalamacchia shortly thereafter. At this point, all indications were that O'Brien's road to the majors with the D-backs was not going to be as a catcher. The bottom line is this, while behind the dish O'Brien caught just 25% of all runners that attempted a stolen base and amassed 44 passed balls in his minor league career. These numbers were enough of a red flag that Arizona had to try O'Brien out at other defensive spots to get his bat in the lineup. The problem is, he didn't fare much better elsewhere. While manning the hot corner in 2013 for the Yankees, he committed 18 errors for an absolutely brutal .802 fielding percentage, then made three more errors in the AFL in just seven games at the position. While manning right field in 2014, he made just one error in just 12 contests, then another 10 in 101 games splitting time between both outfield corners for Reno in 2015. O'Brien truly proved that the search for a defensive home is still a work in progress.
Depending on what media outlet you look at, O'Brien is listed anywhere from the 9th best prospect in their system (MLB.com), to the 19th best (FanGraphs). With a log jam of good players at every position that O'Brien could potentially play in 2016, O'Brien looks to potentially be a trade piece or if nothing else another AAA stud for Reno. O'Brien is proof that mashing homers is not enough for a National League team, since you must play a defensive position too.