SPRINGFIELD, Mass. -- Boston Red Sox designated hitter J.D. Martinez believes Major League Baseball's investigation into the 2018 World Series champions will not reveal sign stealing.

"I'm excited for the investigation to get over with, just so they can see there was nothing going on here," Martinez said Saturday at the team's Winter Weekend fan festival.

When asked if he believed the investigation would reveal no wrongdoing, Martinez responded affirmatively.

"I believe that, yes," Martinez said.

MLB opened an investigation Monday to probe claims the Red Sox used video to decode opponent sign sequences and passed the information to their players in 2018, as alleged in a report by The Athletic.

Martinez played a critical role as an offensive catalyst in the Red Sox's run to a title in 2018 and has been a mainstay in the lineup during his two seasons in Boston, while gaining a reputation with the media as a straight shooter. When pushed by reporters about why he was so strong in his belief, Martinez did not budge from his stance, saying that the team did nothing wrong.

"I was in there, so I saw straight up," Martinez said. "Everyone seems to forget that in 2016 and 2017, this was a really good team. They won 93 games those two years and then we just got better. Like I said, I'm excited for it. Really not allowed to comment on it, but we'll see what happens."

Martinez, who hit .304 with 36 home runs, 33 doubles and 105 RBIs in 2019, also commented on his friendship with pitcher Mike Fiers, who went on the record about Houston's sign-stealing scheme to The Athletic, kicking off the entire scandal. Martinez and Fiers were teammates at Nova Southeastern and have been friends for a long time.

"It sucks for Fiers," Martinez said. "I've talked to him about it. I understand his side of it. I understand his side of being in the division and going against those guys; it's one of those things where he's in an uncomfortable position for him, and I understand it."

The Red Sox parted ways with manager Alex Cora on Tuesday. Cora was the Astros' bench coach before landing the Boston job and "played a central role in what happened in Houston," team chairman Tom Werner said.

So with less than a month before spring training, Red Sox chief baseball officer Chaim Bloom has begun his search for Cora's replacement. Martinez said he thinks bench coach Ron Roenicke is a strong candidate to be the next Red Sox skipper.

"I guess it's up to Chaim to pick that," Martinez said. "I could definitely see it coming from within. Ron is a great candidate and he knows our team, so I wouldn't be surprised if it's him or something. I don't know."

Even with the instability in the manager's office at Fenway Park, Martinez believes the 2020 Red Sox will be fine, given the continuity in the clubhouse among players over the past few seasons.

"This is a group of professionals and a very talented team," Martinez said. "You look at our team and there's a lot of talent, a lot of guys that know how to play the game, and I'm excited. Guys are only going to get better and continue to grow. Look at [Rafael] Devers last year. Who's to say he's not going to grow?

"Christian Vazquez is going to get better. Jackie Bradley Jr. will have a bounce-back [season]. Andrew Benintendi will get better. These are all relatively young guys that are still forming and coming into their own. I'm definitely excited because the injuries that happened with Chris Sale last year, with David Price, those are two big guys for us. How Eduardo Rodriguez threw the ball last year, there's a lot of room for growth here. Not a lot of guys coming out of their prime. A lot of guys going into it."