Sure, the Orioles have only played five games (they are 1-4), so it's obviously still early in the season -- and that's going to be true for the next few weeks. (Also: obligatory small sample size reminder.) But the O's still have not played well. In three games against the Red Sox and two against the Tigers, the O's have been outscored 28-17. So this is a situation in which both the pitching and offense have not performed that well. But, to focus on the starting rotation, only one starter has managed to complete six innings.
Here are the pitching lines in the first five games:
Chris Tillman: 5.0 IP, 7 H, 1 ER, 1 BB, 4 K,
Ubaldo Jimenez: 6.0 IP, 5 H, 4 ER, 3 BB, 6 K
Wei-Yin Chen: 5.2 IP, 12 H, 4 ER, 0 BB, 5 K
Miguel Gonzalez: 3.1 IP, 9 H, 7 ER, 1 BB, 1 K
Bud Norris: 5.0 IP, 9 H, 5 ER, 0 BB, 2 K
In those 25 combined innings, O's starters have allowed 42 hits, 21 runs, and six home runs. They've struck out 18 (6.48 K/9) and walked five (1.80 BB/9), and they have also hit three batters.
So let's start with the hits. 42 hits is a ton in just 25 innings. Clearly O's starters have been unlucky in balls in play, but it's certainly possible to be both unlucky and bad. Unsurprisingly, O's starters have the highest BABIP (.414) in the majors; the next closest is the Rangers (.355). That number should start to drop soon.
The low number of walks is good, while the three hit batsmen is a little odd and fluky (the O's only hit 27 batters with pitches in all of 2013). But there are a few concerns: strikeouts, ground balls, and home runs. With the addition of Jimenez and the loss of Scott Feldman, the O's should gain some strikeouts (and walks). But Jimenez is not a high ground ball pitcher like he used to be. Last year, he had a 43.9 GB% -- a number that's still more than the career ground ball percentages for Tillman (37.7%), Chen (35.8%), Gonzalez (37.1%), and Norris (40.2%) -- and his career average is 47.4%, but his better ground balls years came in his time with Colorado (which is one reason why he was so successful in a difficult pitching environment). (Worth noting: Feldman has a career 47.0 GB%.)
The Orioles have a collection of flyball starting pitchers, which is not news. It's also not news to note that the O's don't have a group of high strikeout starters, either. Only Jimenez and Norris have strikeout rates over 8. Tillman and Chen are both around 7, while Gonzalez is closer to 6.5. The fewer strikeouts the O's get, the more opposing batters put balls in play. The fewer ground balls they get, the more balls are getting hit in the air. That means a ton of fly balls. And right now, the O's are both last in the majors in ground ball percentage (25%) and HR/9 (2.16).
Last year, O's starters had a 6.80 K/9 (22nd in MLB) and a 40.0 GB% (29th). The strikeout numbers may end up a little higher, but there's no reason to suggest the ground ball rate will improve much. As you'd expect, O's starters allowed plenty of home runs as well (1.39 HR/9, most in MLB). It's not unreasonable to anticipate similar numbers.