PHOENIX -- Rob Johnson joined the Mets on Thursday in part because they want some offense from their backup catcher. Mike Nickeas wasn't hitting. Johnson might.

But a significant part of why the Mets recalled Johnson prior to their series opener at Chase Field was because of his history with highly regarded prospect Matt Harvey, who made his big league debut against the D-backs. The batterymates spent much of this season together at Triple-A Buffalo, where Harvey counted Johnson among his primary mentors.

"A lot of it had to do with Harvey," Collins said of the transaction that resulted in Nickeas' demotion. "We thought Rob would be the guy to catch him."

That will not necessarily be the case going forward, as Harvey, 23, grows accustomed to pitching in the big leagues. But for the right-hander's debut, the Mets wanted to make sure the atmosphere around him was as comfortable as possible.

That meant waiting to use Harvey until the start of their West Coast swing, allowing him to make his first three starts on the road in front of fewer expectant Mets fans. It meant drawing up plans to remove Harvey from Thursday's game on a high note, if at all possible. And it meant pairing Harvey with Johnson, one of his mentors.

A six-year, part-time big leaguer who joked Thursday that he is "not Crash Davis," Johnson hit .313 during a brief stint with the Mets earlier this year. But for Johnson, offense is secondary compared to his relationship with Harvey.

"I feel like we've pretty much been on the same page for the most part," Johnson said. "Whether he gives up hits, throws balls, gives up a homer or strikes somebody out, we still have to continue to work on his development."

Collins says Thole-Byrdak issue is resolved

PHOENIX -- By the time the Mets touched down in the desert late Wednesday night, manager Terry Collins said, the clubhouse discord that surfaced earlier that day at Citi Field had evaporated.

"It ended yesterday," Collins said prior to Thursday's opener against the D-backs. "We certainly dealt with it. The appropriate things have been said between everybody, and we're going to move on."

The incident in question stemmed from an argument between catcher Josh Thole and reliever Tim Byrdak, who jawed at each other in the dugout following an on-field disagreement about pitch selection. Byrdak later apologized to Thole, though Collins did not take issue with the argument itself; the manager was more irked that the two fought publicly, in plain view of television cameras.

"You want to come in and throw a tantrum in my office, kick stuff, throw stuff around, fight, whatever you want to do," Collins said. "It's got to be done in here. It can't be done out there."

Mets want Duda to focus on hitting in Minors

PHOENIX -- The primary goal of Lucas Duda's recent Minor League demotion is for Duda to right himself at the plate. With that in mind, the Mets originally said that he would play his natural position of first base at Triple-A Buffalo, in an effort to allow him to concentrate more fully on hitting.

But Duda made his Bisons debut Thursday in right field, the same position he had played exclusively with the Mets. That may be temporary. Should Duda at all scuffle in the field going forward, manager Terry Collins has given Buffalo manager Wally Backman free reign to move Duda back to the infield.

"He's got to be comfortable, so when he gets in that batter's box, that becomes the primary focus," Collins said, noting that he still sees Duda as a right fielder long-term in the big leagues. "He cannot worry about making a mistake defensively and then come in and say, 'Well, I've got to make up for that error. I've got to hit this ball out of the park.'"

Worth noting

• Collins confirmed that Jeremy Hefner will remain in the rotation, making his second start Monday in San Francisco. Hefner struck out seven over six innings Wednesday against the Nationals, allowing three runs (two earned). He should remain a starter until Johan Santana is ready to return from the disabled list, likely early next month.

• Frank Francisco will make his second rehab appearance on Friday for Double-A Binghamton, but Collins said the Mets will not activate the closer from the DL until he shows some consistency on his Minor League assignment. Francisco gave up two runs over two-thirds of an inning Wednesday in his first rehab appearance.