Alvarez returns to the rotation looking to pick up where he left off Saturday night in his first career start against the visiting Arizona Diamondbacks.Alvarez (8-5, 2.48 ERA) did his best to fill the void left when Fernandez was forced to undergo Tommy John surgery. The right-hander was 6-2 with a 1.73 ERA in a span of 13 starts, earning a trip to the All-Star game before developing inflammation in his throwing shoulder in a 3-0 win over Washington on July 29."Whatever he had is gone and he's ready to go," manager Mike Redmond told MLB's official website. "And a perfect time. We need him. We were all hoping that this was a short-time deal, and it looks like it is, so that's big for us."Alvarez has already thrown 10 2/3 more innings than he did last year between Triple-A and the majors, and admits he isn't quite 100 percent. Still, he seems relieved to be back."The rest has definitely helped me," Alvarez said. "I rested my whole arm and now I get to start again. I'm just glad I can come back, and I hope I'll stay healthy so I can finish out strong."Miami (60-62) has won 12 of Alvarez's past 14 starts and could use his help in its attempt to make up a significant deficit in the NL wild-card race. After winning 5-4 in 10 innings in Thursday's opener, Miami couldn't overcome first-inning homers from Aaron Hill and Cliff Pennington that resulted in all the runs the Diamondbacks would need in Friday's 3-2 victory.The Marlins got their runs in the bottom half on singles from Giancarlo Stanton and Garrett Jones, but hit into four double plays."They hurt us tonight for sure," said third baseman Casey McGehee, who grounded into two of the four. "It's going to happen from time to time, but it doesn't make you feel any better about it."The Diamondbacks (53-69) have claimed back-to-back victories just twice since July 20 and Wade Miley (7-8, 4.61) will try to make it two straight again while building on an improved outing.The left-hander was tagged for a career-worst 10 runs and nine hits in 4 2/3 innings of a 12-2 loss to Kansas City on Aug. 5, but gave up three runs in six innings Sunday against Colorado. Miley also fanned eight Rockies in a 5-3 loss in 10 innings.He might be happy to be making his fourth career start against the Marlins. Miley is 2-1 with a 0.89 ERA in the three previous matchups.Jordan Pacheco is the only active Diamondbacks player with more than one hit off Alvarez, going 2 for 2.