ST. PETERSBURG -- By Monday night, the hard part was already behind Merrill Kelly. He’d toiled in the Minors, moved to Korea then returned to begin his stateside career anew.

He’d won his Major League debut, casting aside any lingering doubts anyone -- including he -- might have had that he was finally where he belonged.

When he took the mound on Monday to face the team that had drafted him, Kelly carried no chip on his shoulder, maintaining all along that he had no hard feelings against the Rays. He was, he said, simply content to perhaps run into some of the old crew.

The Rays’ greeting was anything but kind, however, as they touched their former teammate for seven runs during a 12-1 victory over the D-backs at Tropicana Field in the series opener.

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“[There was] not much good, I know that. It was just all-around just a bad one,” Kelly said. “One of those games that I’m going to home tonight and try to flush it and kind of move on to the next one.”

Tampa Bay scooped Kelly in the eighth round of the 2010 MLB Draft. From there, he rose to Triple-A and had what was probably the best season of his Minor League career in 2014, finishing 9-4 with a 2.76 ERA at Durham. But the Rays opted not to make him a late-September callup and didn’t protect him prior to the Rule 5 Draft.

So the right-hander took a career gamble and opted to hone his craft in Korea, becoming the first player with no MLB experience to play there and then jump directly into his big league debut. While experiencing success overseas, he perfected his secondary pitches and his strategy, and added 3 mph to his fastball.

Kelly toted a 2-0 record and 2.19 ERA over his past two starts into Monday’s matchup, feeling good about his progress in the young season.

Nerves appeared to get the better of him out of the gate. Kelly issued a five-pitch leadoff walk to Brandon Lowe, whose bat didn’t move from his shoulder. The following hitter, Tommy Pham, skidded a base hit up the middle to put runners at the corners.

The next pitch Kelly issued -- a curveball in the dirt -- just missed hitting Ji-Man Choi, who eventually grounded into a fielder’s choice to score the Rays’ first run.

“The first three [innings] were, I want to get them out of my mind,” Kelly said. “I want to get that feeling, those pitches, those locations, I want to get them out of my mind as fast as possible, because it wasn’t good, and I want to be able to hone in on the good stuff and move forward.”

It didn’t get any better from there. The Rays touched Kelly for consecutive singles to open the second. The rookie coaxed Kevin Kiermaier into a lineout, hit Mike Zunino to load the bases then walked Daniel Robertson on six pitches to force home another run.

A quick mound visit seemed to set Kelly back on the right track, as he fanned Lowe on three pitches. The situation reversed itself two pitches later, though, when Pham took Kelly deep to straightaway center field for the first grand slam of his career.

“It wasn’t a typical Merrill outing, I know that,” D-backs manager Torey Lovullo said. “He’s been very good. He’s been very good for us. Every once in a while, we expect hiccups. He’ll go back to the drawing board, get four days full of work and see what he can do the next time.”

By the time he’d labored through a 31-pitch third inning that ended with Lowe's bases-loaded fly ball to the warning track in straightaway center -- this one caught -- Kelly’s pitch count was 77 and the D-backs’ bullpen was stirring. The 30-year-old rebounded to sit down the side in order in the fourth, but it marked the end of his night.

Kelly was replaced in favor of Zack Godley after allowing seven earned runs on seven hits, three walks and a hit batter. He struck out two.

Whether an off night or something to do with this particular opponent -- perhaps a little of both -- Kelly is eager to wipe the slate clean and begin anew tomorrow.

He has traveled much too far already to let one bad start keep him down for long.