CINCINNATI -- When the Reds signed free agent swingman pitcher Nick Martinez in December to a two-year, $26 million contract, they saw value in the right-hander as both a starter and reliever.

Nick Lodolo has been on the injured list twice this season, and twice Martinez was able to step from the bullpen into the rotation without having to call up another starter.

Martinez's best performances this season have been as a reliever. As a starter? Not so much. And that was the case again during a 7-3 Reds loss to the Padres on Wednesday at Great American Ball Park.

“I felt like my game plan was there, but it came down to execution," Martinez said.

Cincinnati, which took the series opener, has dropped 16 of its last 20 games and is still searching for its first back-to-back wins since April 23-24. The club's 6-18 record since April 25 is worst in the Majors.

Martinez pitched 4 2/3 innings and allowed five earned runs and eight hits with one walk and two strikeouts.

In six appearances as a reliever, Martinez is 1-0 with a 1.04 ERA. His previous outing, on Thursday at the Dodgers when Lodolo went on the IL the day prior, was a five-inning scoreless relief appearance with one hit after the club used an opener.

Over five starts for the Reds, Martinez is 0-3 with a 7.36 ERA. Conversely, he had a 2.32 ERA in nine games as a starter last season for San Diego and a 4.12 ERA in 54 relief appearances.

“To be honest, I don’t think there’s been much of a difference," Martinez maintained about starting vs. relieving. "There’s been some bad breaks as a starter with weak contact falling into no-man’s land or getting ground balls. Today was probably the most different of all my starts and all my outings. I didn’t execute as well as I normally do.

"I thought I’ve done a good job up to this point of executing those sliders down and away, missing down and away and off the plate. Today, it got a lot of the plate to a lineup that feasts on offspeed in the zone.”

In the first inning, Luis Arraez led off the game by hitting Martinez's full-count cutter for a homer to right field. Jeimer Candelario evened the game for the Reds in the bottom of the first with a two-out homer to right-center field against Padres starter Michael King. Following the Arraez homer, Martinez settled in and retired eight of his next 10 batters.

A leadoff walk from Jurickson Profar in the top of the fourth led to another run for the Padres. Manny Machado scored a hard one-out double that put two runners in scoring position. With the infield playing in, David Peralta hit a grounder to second base, but Jonathan India's throw to the plate was up the line and not in time as Profar scored.

More trouble mounted with four hits for three more runs in the fifth, including hard-hit singles by Luis Campusano, Tyler Wade and Fernando Tatis Jr. on early-count pitches. Martinez's final batter, Profar, hit an RBI double through the gap in left-center field to make it a 5-1 game.

“Definitely could have gone different. He kept us in the game," Reds manager David Bell said. "The fifth inning got away from us a little bit. Just missing with some pitches, some really close pitches that he wasn’t getting. That really was the difference. It made it a little tougher on him tonight.”

Lodolo, who has been out with a left groin strain, is eligible for activation on Monday. He threw a side bullpen session on Wednesday afternoon, but the big question Thursday will be if he recovered well. If so, the left-hander would be a good bet to return, and Martinez would return to the bullpen.

Should the Reds lose a starter to injury down the road, they could have another option in Brandon Williamson. The lefty, who has been on the IL since Spring Training because of a left shoulder strain, is currently on a rehab assignment with Triple-A Louisville.

Despite the statistical disparity in Martinez's work as a starter and reliever, Bell still believed Martinez can successfully work in both roles.

"I really think that’s going to come around," Bell said of Martinez's starter numbers. "He’s incredible, the attitude of wanting to be involved and do whatever it takes for our team to win games. So we’ll have to see how it plays out for getting most of his time, but if he continues to go back and forth, I think it will even out by the end of the year.”