Aaron Cook gashed his right knee while covering home in the second inning Saturday. (Photo from Twitter account of Danny Kurash)

The Red Sox opted-out of another win Saturday.

Aaron Cook’s first start since joining the Red Sox’ roster — a move that was partly necessitated by the pitcher’s chance to opt-out of his deal with the team at the beginning of May — didn’t go as planned. Cook allowed seven runs on eight hits over 2 2/3 innings while taking the loss in the Orioles’ 8-2 win over the Sox at Fenway Park.

The outing was Cook’s worst of his career since Aug. 16, 2009 against the Marlins, and lasted 48 pitches. Most of the damage by the Orioles was done in a seven-run third inning, in which which all the runs were scored with two outs. The pivotal frame also came after Cook suffered a sizable gash on his left knee after being cleated by Baltimore’s Chris Davis in a play at the plate in the second inning.

The Red Sox have now lost four in a row, dropping to 11-15.

Here is what went wrong (and a little of what went right) in the Sox’ loss:

WHAT WENT WRONG

- The Orioles scored their first run when Chris Davis slid home safely on Jarrod Saltalamacchia’s passed ball with two outs in the second inning. Not only did the run score, but Davis’ cleat caught the right knee of Cook, who was covering home. The play resulted in the pitcher having to go the dugout to get stitched up, while reliever Clayton Mortensen ran in from the bullpen just in case Cook couldn’t return.

- Nick Markakis plated the visitors’ second run with a two-out single, scoring J.J. Hardy. The hit came on an 88 mph 3-1 sinker.

- Adam Jones launched a two-run homer well over the left field wall with two outs in the third inning. The outfielder hit his seventh homer of the season on a 0-2 curveball from Cook.

- Wilson Betemit’s two-out RBI single capped Cook’s outing, with the starter leaving with two runners on and the Orioles holding a 5-0 lead. It marked the fifth consecutive hit for the O’s with two outs in the inning.

- During Matt Wieters’ fifth-inning at-bat, the catcher launched a pop-up in foul ground between home and third base. Third baseman Nick Punto and Saltalamacchia let the ball drop between them, prolonging the at-bat.

- The Red Sox couldn’t figure out Orioles’ starter Jason Hammel, whose ERA stands at 2.09 after he allowed two runs on four hits over 6 2/3 innings.

WHAT WENT RIGHT

- Other than giving up a monstrous two-run home run to Mark Reynolds on the first batter he faced, Sox reliever Clayton Mortensen impressed once again. The righty finished his 3 1/3-inning outing giving up one run on two hits while striking out five and not walking a batter. He finished throwing 57 pitches.

- Ryan Sweeney produced the Red Sox’ first run, plating Gonzalez with a two-out double off the left field wall. It moved the outfielder’s batting average to .359. He would be promptly driven in by Cody Ross one batter later via a single to right.

- With one out in the third inning, and runners on first and second, Endy Chavez was gunned down trying to steal third by Sox catcher Jarrod Saltalamacchia.

- The Red Sox had taken the right approach in the first inning, forcing Hammel to throw 26 pitches. Punto had gotten things going with a nine-pitch at-bat to leadoff the game. The problem came when the Sox’ stranded two runners in the frame, leaving them at 6-for-44 with runners in scoring position for the homestand at the time. Hammel finished at 115 pitches.

- Gonzalez finished with three hits for the second straight game, boosting his average to .284.

- Scott Atchison turned in another solid relief outing, not allowing a hit or run in 2 2/3 innings. The righty carries a 1.50 ERA, having not given up a run in any of his last five relief outings.