The major-league roster limit expands from 25 to 40 players on September 1. Every year, teams recall or add players to the major-league roster from their minor league affiliates. The Orioles, who are now contending for a playoff spot, are more likely to promote role players and depth rather than prospects. It's simpler for them to promote players who are already on their 40-man roster.
As of Tuesday, August 6, there are 39 players on the Orioles' 40-man roster and two on the 60-day disabled list, which doesn't count against the 40-man roster. That means there are 14 players on the 40-man who aren't on the Tides' active roster. One is Jason Hammel, on the 15-day disabled list; a second is Dylan Bundy, who is parked on the Bowie roster while he recovers from season-ending surgery. All 12 of the remaining players are on the Norfolk Tides' roster. I'll review these 12 candidates for a September call-up.
Of course, the Orioles aren't limited to these players on the 40-man roster. Chris Dickerson and Freddy Garcia, among others, are playing for Norfolk but aren't on the 40-man roster. The Orioles could still promote them but they'd have to create space on the 40-man roster to do so.
Xavier Avery: Although Avery has regressed in 2013 (2012: .236/.330/.356; 2013: .223/.302/.303 at Norfolk) I would not be surprised if the Orioles called him up. He still can run and his outfield range is still good. That makes him useful as a bench player on an extended roster, and he's almost the only potential call-up with above-average speed. He was with the Orioles in 2012, so if he is called up, it will be as a pinch-runner / defensive replacement.
Mike Belfiore: It's something of a surprise that Belfiore is still on the 40-man roster considering that he's been pitching long and mop-up relief in Norfolk. This season, he's been recalled to Baltimore twice and has been sent back before pitching in a game. He has struck out a fair number of hitters (69 in 60 2/3 innings pitched) but has also allowed too many home runs (8), six of those being hit by left-handed batters. Belfiore doesn't deserve to be recalled and doesn't project to be a helpful addition, but the Orioles might recall him if they decide they need another left-hander in the bullpen.
Zach Britton: Britton is very likely to be recalled for September. He's made six starts for the Orioles earlier this season and wasn't bad enough to pitch himself out of the Orioles' future. The Orioles might recall him for use as a spot starter/long relief man. He hasn't pitched well at Norfolk, and I mean that literally - he has a 6.57 ERA at home, and a 3.46 ERA on the road (with significantly more unearned runs allowed at home as well.)
Steve Clevenger: Clevenger is an ideal candidate for a September call-up. He's one of three catchers on the 40-man roster, and his addition will give the Orioles more flexibility. He's a left-handed hitter, which is a positive. He's also played first base, and he might allow the Orioles to rest Chris Davis as a DH more safely. Clevenger was recently activated from the disabled list, and I've only seen him play games so far.
Kevin Gausman: Gausman will almost certainly be called up in September. He's pitched with the Orioles before, can be used as both a spot starter or reliever, and is a young, top prospect. The Rays promoted both David Price and Matt Moore to be bullpen arms in their postseason hunts, and Gausman is similar to them in that he's a young, dynamic arm. Gausman hasn't pitched as well at Norfolk as I would have hoped; from what I've seen (in only two starts) his fastball has velocity but little movement and he gets hit more easily than you'd expect. Despite that, I think he'd be an excellent addition to the Orioles' bullpen for their postseason push.
Steve Johnson: Johnson is another pitcher who will likely be called up. He's missed most of this season because of injuries, but pitched very well down the stretch in 2012. He also has major-league experience as both a starter and a relief pitcher. He is currently working his way back into condition at Norfolk.
Alex Liddi: Liddi, who was acquired from the Mariners after he had been designated for assignment off the Mariners' 40-man roster, is unlikely to be called up. He's a poor man's Danny Valencia - a right-handed hitting corner infielder but not as good a hitter. Because both he and Valencia would serve the same role, it doesn't make sense to promote both and of the two. Valencia would be the choice.
Jonathan Schoop: If the Orioles were out of contention, then they would likely promote Schoop. He's the best in-house, long-term option at second base, and he would likely be given some looks. But because the Orioles are in contention, he wouldn't be likely to get much playing time. And Schoop is recovering from a stress fracture in his back. I think the Orioles are more likely to send Schoop either to the instructional league or the Arizona Fall League to continue his recovery. Schoop has been playing fairly well at Norfolk but hasn't been dominant.
Josh Stinson: Stinson, who was promoted to the Orioles to make one spot start, is still on the 40-man roster. He hasn't pitched badly for Norfolk, but he hasn't pitched extremely well either. He's mainly pitched as a starter in 2013, and he doesn't have the dominant stuff teams like to have in their bullpen. I don't think the Orioles are likely to recall him.
Eric Thames: Thames is an interesting case. He's a left-handed hitting outfielder with fairly good speed and fairly good power. He's been playing well at Norfolk (.324/.372/.493 in 19 games, 71 at-bats; 3 stolen bases) since he's been acquired from Seattle. Because he hits left-handed, he might be recalled to be a backup outfielder.
Danny Valencia Valencia is almost certain to be recalled. He's been up with the Orioles for 25 games and has hit with power. He's continued to hit at Norfolk. He'll be recalled to be a right-handed PH/DH who can also play first base if Chris Davis needs to play DH for a day's rest.
Tsuyoshi Wada: I don't think the Japanese left-handed starting pitcher is likely to be called up. Wada has pitched very well recently; he has a 1.99 ERA in his last four starts, covering 22 1/3 innings. And his fastball velocity has improved from the mid-80s to 90-91. On the other hand, Wada is being handled very gingerly. Because he is recovering from arm injury, and because he pitched in Japan with five days' rest, he's rigidly starting only every sixth day for the Norfolk. Even though the Tides have a six-man rotation, on Monday's doubleheader the Tides pitched Game 2 as a bullpen game rather than pitch Wada on "only" four days' rest. Consequently, it's unlikely that Wada would be used in a bullpen role. His stuff and game are very similar to Zach Britton's, and I think the Orioles are more likely to recall Britton than Wada.