The St. Louis Cardinals, looking to fortify their starting rotation as they battle the Milwaukee Brewers and Pittsburgh Pirates in the National League Central, have acquired Justin Masterson from the Cleveland Indians.

Masterson, who will come off the disabled list (knee) later this week, has a 5.51 ERA, 1.65 WHIP and 93 strikeouts in 98 innings this season. The Cardinals will send outfield prospect James Ramsey to the Indians in exchange for the 29-year-old right-hander.

The Cardinals were linked to bigger names like Jon Lester and David Price leading up the deal with the Indians. Reports are conflicted as to whether landing Masterson takes St. Louis out of the running for the pair of left-handers.

Masterson, who will be a free agent after the season, discussed a potential contract extension with Cleveland until negotiations broke off early in the spring without a resolution. Masterson, who was an All-Star last season, was believed to be seeking a multiyear deal at more than $15 million annually.

Just a season ago, Masterson went 14-10 with a 3.45 ERA, 1.20 WHIP and 195 strikeouts in 193 innings. The Cardinals are hoping his latest stint on the DL has fully rectified his knee issues and will lead to a more productive remainder of the season.

Will Carroll of Bleacher Report tweeted soon after the trade that it wasn’t an indication that St. Louis is worried about Michael Wacha, who they still expect to return this season.

The Cardinals, who entered Wednesday two games back in the NL Central, have the eighth-lowest ERA (3.39) in the Major Leagues. However, they rank in the lower half of baseball in quality starts, which has taxed their bullpen slightly.

Adam Wainwright has been otherworldly and Lance Lynn has been a revelation, but the remainder of the staff is a question mark.

Wacha was great early in the season, but he’s unlikely to return until September. Shelby Miller and Carlos Martinez, 23 and 22 respectively, have endured growing pains as starters. Jaime Garcia (4.12), Joe Kelly (3.90), Tyler Lyons (5.79) and Marco Gonzales (7.07) have made 20 starts, largely disappointing each time out.

The Masterson that pitched for the Indians in the first half of the season isn’t a much better option than the four pitchers mentioned above, but a healthy and re-energized one would help push the reigning National League champions back to the postseason.

Grade for Cardinals: B-

Cleveland didn’t have a reason to hold onto Masterson. Not only had he struggled, but they are on the outside of the American League playoff race and clearly felt his agent valued the right-hander more than they did.

Grade for Indians: A-

Ramsey was an expendable piece for the Cardinals, who have a series of outfield prospects in the pipeline. A first-round pick in 2012, MLB.com recently ranked him as St. Louis’ No. 6 prospect. Evaluators are concerned about how his power will develop because of a small frame and aggressiveness at the plate.