O'Brien hit his first career big league home run as a pinch hitter in Friday's loss to the Astros.

O'Brien has played sparingly in his September cup of coffee with the D-Backs, but it's nice to see him show off the power that is his calling card. His future role with Arizona remains uncertain, but if and when he earns playing time in the majors, he will hit a fair number of home runs as his back-to-back 20-homer seasons in the minors attest.

While he hasn't played much since being recalled, O'Brien has been doing catching drills with the Diamondbacks coaching staff and the team remains open to him returning behind the plate, reports Nick Piecoro of the Arizona Republic.

O'Brien last caught in a game for Triple-A Reno on May 29 before playing the rest of the season in the outfield, but it sounds like the D-Backs are still not prepared to give up on the idea of him as a catcher. While adding catcher eligibility would increase his potential fantasy value significantly, this remains a very tentative proposition based on this report. It will be worth keeping an eye on O'Brien's position if he plays in any off-season or winter leagues, and of course where he lines up in spring training 2016.

O'Brien singled and drove in a run in his first major league at-bat Friday in a blowout win over the Dodgers.

This was O'Brien's first game action since being recalled on Tuesday. He should get a handful of at-bats down the stretch with Arizona's outfield pretty full, but after posting a .284/.332/.551 with 28 home runs and 107 RBI at Triple-A Reno he should have an opportunity to play his way into the discussion for playing time in 2016.

O'Brien was called up from Triple-A Reno on Tuesday.

O'Brien followed up his 34-homer campaign in 2014 with a 26-homer season in his first year at the Triple-A level. The 25-year-old also trimmed his strikeout rate to 23.2 percent, which is certainly an acceptable mark given his power, and also got on base at a decent .332 clip. However, he was moved to the outfield full-time halfway through the season, and with the Diamondbacks' starting outfield well set, it appears O'Brien's opportunities may be limited to spot starts and pinch-hit appearances.

O'Brien had himself a night for Triple-A Reno on Wednesday going 3-for-4 with two hone runs and a double, driving in four and scoring three times.

O'Brien's is having a good first full season in the D-backs' system - his 23 home runs rank third in the Pacific Coast League and his .286/.334/.543 line has met expectations. Having moved out from the behind the plate, his path to the D-bakcs is blocked by a solid group of outfielders who already share playing time. While his top line stats look strong, they are also propped up by a .330 BABIP and mask an on-going challenge with his approach (his walk rate is just 5.7%). He might see a cup of coffee when rosters expand in September, but he's not close to earning a spot on the D-backs' roster just yet.

O'Brien is batting .272/.318/.513 with 17 home runs for Triple-A Reno.

After getting off to a very hot start, O'Brien's season line looks almost exactly like his career .269/.319/.529 minor league line. He hit three home runs in both June and July after slugging 11 in the season's first two months. Given that he no longer catches, O'Brien is now looking like a big power, low OBP corner outfielder and his future major league role is a question mark.

O'Brien is batting .307/.348/.566 for Triple-A Reno and hit his 14th home run Friday.

This was just the slugger's second home run in June, as he has slumped at the plate recently collecting just nine hits in his last 42 at-bats (.214 average). While Yasmany Tomas is not expected to need a DL stint, after getting hit on the elbow with a pitch Friday, O'Brien's name will be discussed as a replacement any time one of the D-back's corner outfielders suffers an injury. O'Brien has played the outfield exclusively since late May, a sign that his days as a catcher could be over, although that has not been made official.

O'Brien will move to the outfield full-time, according to a report from Steve Gilbert of MLB.com.

The timing of the decision seems curious with the injury to starting catcher Tuffy Gosewisch, but O'Brien has been considered a candidate to move out from behind the plate for most of his minor league tenure. He is hitting .337/.377/.641 for Triple-A Reno and will now focus on developing as an outfielder where his path to the majors is less straight forward since the D-Backs have a number of decent options ahead of him.

O'Brien was not recalled from Triple-A Reno when D-Backs' catcher Tuffy Gosewisch went down with a knee injury because he still needs more reps behind the plate, reports the Arizona Republic's Nick Piecoro.

This isn't exactly surprising as there have been questions about O'Brien's defense for some time and he has just 10 games at catcher this year. Manager Chip Hale has positive things to say about his progress, but it is clear that despite his .343/.385/.657 and 12 home runs he will have to do more defensively to get called up to the D-Backs.

O'Brien is batting .344/.382/.669 with 11 home runs, 44 RBI, and 30 runs scored in 170 plate appearances for Triple-A Reno.

O'Brien's 1/051 OPS leads the Pacific Coast League and he ranks third in home runs. While he is still striking out in 20 percent of his plate appearances, that is down a fair bit from his previous minor league seasons. The D-Backs continue to give O'Brien time behind the plate, but the view among other evaluators is that he can't handle the position in the majors. With his power, the bat will play somewhere.

O'Brien caught his first game of the season at Triple-A Reno on Wednesday, FOX Sports Arizona's Jack Magruder reports.

He also hit is eighth home run of the season, so O'Brien's ability with the stick is not what is at question here. O'Brien started the year playing the outfield in an attempt to give him a break from the mental aspect of catching, but his quickest route to the big leagues would be as a catcher, so this is good news. However, there's also a fairly decent chance that his defense behind the plate becomes an issue, or his offense suffers because of his attention to catching. It will be an intriguing situation to monitor going forward.

O'Brien launched his seventh home run of the season Tuesday as part of a 3-for-4 day for Triple-A Reno.

O'Brien is enjoying life in the friendly batting environments of the Pacific Coast League, posting a .397/.436/.781 line in the early going. He is still playing exclusively in the outfield, which makes his route to Arizona a bit tougher as they have plenty of outfielders at the moment. O'Brien is making a lot more contact and has reduced his strikeouts significantly so far, but with just three walks drawn to date, he still has stuff to work on at the plate.

O'Brien homered for the third straight day, giving him six on the season, to go 1-for-3 with a run, an RBI, and a walk Wednesday for Triple-A Reno.

O'Brien continues to show off big power and has now drawn a walk in consecutive games too. He is batting .426/.466/.852 on the season, but despite the impressive line the Diamondbacks have no where to put him in the outfield, and he hasn't returned to catching yet, so he is not likely to come up any time soon.

O'Brien homered for the second consecutive day, giving him five on the season, as part of a 3-for-4 day with two runs scored and an RBI, for Triple-A Reno.

O'Brien also drew his first walk of the season. He is hitting .431 on the season and continues to show off impressive power.

O'Brien went 3-for-4 with his fourth home run of the season Monday for Triple-A Reno. He scored twice and drove in two runs.

O'Brien keeps hitting, raising his line to .404/.429/.766 after this performance. The question remains whether he can field a position well enough to stick in a major league lineup. He played left field in this one, while the D-Backs maintain that the move to the outfield isn't permanent and he can be expected back behind the plate in the coming weeks. Of note, O'Brien is still yet to draw a walk this season through 49 plate appearances.

O'Brien 2-for-4 with his third home run of the season and three RBI on Saturday for Triple-A Reno.

The slugger has a .375/.390/.700 batting line so far for Arizona's AAA affiliate. He continues to work in the outfield, but the club has indicated he will get back behind the plate at some point. O'Brien continues to show off the power that is his calling card, but he has yet to draw a walk through 41 plate appearances this season, which suggests he has some work left to do in his development as a hitter.

O'Brien is getting a mental break from catching as he works through throwing issues, the Arizona Republic's Nick Piecoro reports.

He has moved to the outfield as the D-Backs attempt to let him clear his head before hopefully returning to catching in a month or so. The fact that this even needed to happen shows how sketchy O'Brien is defensively behind the plate, and while it's possible he could catch at some point in the big leagues, it's much more likely that he ends up as an outfielder or a first baseman long term.

O'Brien had another big day for Triple-A Reno, going 4-for-5 with a double, a run scored, and an RBI.

O'Brien is 9-for-20 with a couple of doubles, a home run, and five runs scored to start his time in the Arizona system. He is yet to draw a walk, but that's the only downside to his performance thus far. He is making the transition from catcher to outfield, which makes his path to the majors less clear as Arizona has plenty of outfielders ahead of him, but if he keeps hitting a spot will be found for him.

O'Brien had a huge day Thursday for triple-A Reno, going 3-for-5 with a homerun, three runs scored and three RBI.

O'Brien played right field in this one, which may be a hint that the Diamondbacks are ready to give up the idea that he can be a catcher. His ultimate position will determine both his path to the majors and his fantasy value, so it bears watching. What is clear is that the power he showed slugging 34 homeruns across three minor league levels last year plays at any position.

O'Brien is being listed as an outfielder rather than a catcher at Triple-A Reno.

That's always been the debate about O'Brien - can he stick behind the plate? He came down with a case of Macky Sasser disease in spring training, struggling to throw the ball accurately back to the pitcher. We'll see if this is a permanent change or not, but clearly it hurts his value.