(Sports Network) - Right-hander Clay Hensley gets his first post-trade opportunity in the San Diego starting rotation tonight when the Padres visit the Pittsburgh Pirates in the first of four weekend games at PNC Park.

Hensley, who's not started since last August and has made just three relief appearances this season, gets the call in place of left-hander Randy Wolf, who was dealt to Houston earlier this week.

He won 11 games in 37 games - 29 starts - for the Padres in 2006, then was 2-3 in 13 games (nine starts) a season later.

Hensley's pitched three times this month, allowing just a hit in five scoreless innings and getting credit for a 6-4 victory at Cincinnati on July 21

Rookie right-hander Yoslan Herrera gets his third start for the Pirates.

The 27-year-old made his debut on July 12 against St. Louis and picked up a no-decision in a 12-11 win after allowing 11 hits and six runs in 4 1/3 innings.

He returned seven days later and was hit even harder, giving up eight hits and seven runs in just 1 2/3 innings of a 7-1 loss at Colorado.

A 6-foot-2, 200-pounder, Herrera was an undrafted free agent.

On Wednesday in Cincinnati, Adam Dunn belted his eighth career grand slam and drove in five runs as the Reds charged past the Padres for a 9-5 win in the rubber match of a three-game set at Great American Ball Park.

Padres starter Greg Maddux allowed three runs -- two earned -- on seven hits in 5 1/3 innings and didn't factor in the decision. Maddux is now winless over his last 14 starts since his 350th career victory May 11 against Colorado, establishing a new career-long skid. Maddux previously went without a win for 13 starts from May to July 1990.

Jody Gerut and Kevin Kouzmanoff each homered and knocked in two runs for the Padres, who have lost nine of their last 11 games. Brian Giles notched an RBI single, while Luis Rodriguez scored a pair of runs.

Cla Meredith (0-3) allowed the go-ahead run to take the loss in relief of Maddux, while Joe Thatcher was ripped for five runs in two-thirds of an inning out of the bullpen.

In Houston, Doug Mientkiewicz went 4-for-4 with a pair of runs batted in and the Pirates won a wild 8-7 decision over the Astros in the finale of a three- game series at Minute Maid Park.

Jason Bay belted a two-run home run for the Pirates, who pulled off a sweep of Houston on the heels of a five-game losing streak. Xavier Nady and Freddy Sanchez each went 2-for-5, while Nate McLouth reached base three times and scored twice.

Franquelis Osoria (4-3) tossed two perfect innings to earn the win in relief of Ian Snell, who was battered for five runs on six hits in three innings. Damaso Marte worked a scoreless ninth to notch his fifth save.

San Diego was 6-1 against the Bucs last season and has won 11 of the 13 meetings since the start of the 2006 campaign.