(SportsNetwork.com) - Pittsburgh's transient pitching staff has been the engine behind the team's recent return to relevance.

The Pirates will turn to veteran Charlie Morton to continue that trend -- and get them another game above the .500 mark -- when they visit Tropicana Field on Wednesday afternoon to close out a three-game series with the Tampa Bay Rays.

Pittsburgh's rotation -- three-fifths of which was elsewhere to begin the season -- has posted a 2.17 earned run average during a four-game win streak that included a 6-5 victory in Tuesday's game. The Pirates were eight games below .500 on May 6, but they've put together baseball's best record, 27-18, to move above .500 for the first time since they were 7-6.

Morton was touched for six runs in six innings in his last start against the Chicago Cubs on Friday, but he'd been 4-1 in five starts coming in while compiling a 2.40 ERA.

Still, he's never quite gotten over the interleague hump, going 0-5 with a 6.39 ERA in his last six meetings with American League competition.

The Rays, however, have the worst record in the major leagues and have batted just .176 with runners in scoring position across their last 26 games.

They've not done much for ace lefty David Price this season either, and have scored just nine runs for him in his last five starts. He's won just one of four decisions in those starts, but has struck out 49 batters and posted a 2.58 ERA in those 38 1/3 innings.

In the Pirates, he faces a team that's scored 14 runs and rapped out 18 hits in two games to begin the series. They could be without outfielder Starling Marte for the concluding game after he sustained a head injury while trying to steal a base on Tuesday.

He was hitting .356 in his last 14 games.

On Tuesday, Andrew McCutchen drove in a pair of runs as the Pirates grabbed a win in the second game. Russell Martin hit a solo home run for the Pirates.

Jeff Locke (1-1) allowed three runs on eight hits in 7 1/3 innings to get the win.

Evan Longoria hit a two-run home run, Brandon Guyer added a two-run single and Jose Molina drove in the other run for the Rays.

Chris Archer (4-5) allowed five runs -- four earned -- on seven hits over seven innings.

Tampa Bay won two of three meetings with Pittsburgh back in 2008.