NEW YORK -- As Aroldis Chapman focused on honing his splitter this past winter, the Yankees closer kept a snapshot in his mind, recalling the diving pitches that former big leaguer Jose Contreras once used to baffle hitters. That was the type of pitch Chapman desired, and he might just have achieved that goal.

Chapman's splitter has been a difference-maker early this year, providing the left-hander with a third offering to keep opponents guessing. Chapman had become too predictable with his fastball-slider combination, and the splitter should provide the 33-year-old with a weapon to remain effective even if his fastball loses some heat.

"It’s simple: I like it. I like using it,” Chapman said through an interpreter. “It goes back to when I started pitching; unfortunately, when I was playing for the Cincinnati Reds, they didn't like me throwing that pitch because I was younger at the time and they felt that it was unnecessary. But I've always liked using this pitch.”

Yankees manager Aaron Boone has referred to Chapman’s splitter as “gross” -- in the most positive way. Pitching coach Matt Blake has applauded Chapman’s initiative to revive his shelved offering, noting in addition that Chapman’s velocity has improved over the past two years.

“I think he's becoming a more complete pitcher while also still retaining some of those elite qualities he's had in the past,” Blake said. “It's been really impressive to watch so far, and hopefully we can we just continue to see more of it.”

Chapman has used the splitter nine times this season, and hitters haven’t yet figured out what to do with it. The pitch has generated five strikeouts already, as Chapman rides a franchise-best streak of recording at least two strikeouts in each of his last 14 games, dating to Sept. 3, 2020.

“It goes to how comfortable I feel using the split,” Chapman said. “I couldn't say that I'm completely surprised by the reaction of the hitters, but I am extremely happy with the results. I think it's about using it in specific counts and certain situations. It's something that I worked on a lot, so I’m comfortable with the pitch and definitely happy with the results.”

Vax all, folks
The Yankees are nearing the 85 percent vaccine threshold among their players, coaches and other Tier 1 personnel, according to Boone. Most of the shots were administered at Yankee Stadium on April 7. Reaching the 85 percent threshold will permit the relaxing of protocols in the clubhouse, dugouts and other spaces.

“I think we're as close as you can be to [85 percent], because it factors in the alternate site as well,” Boone said. “Here [on the big league roster], I think we're over 90 percent. I think we're just at about 84 percent still because there's some still pending some people that have gotten a second shot. So we're very close.”

Clubs were informed just before Opening Day that MLB and the MLB Players Association have agreed to relax certain health-and-safety protocols contained in the 2021 Operations Manual for fully vaccinated Tier 1 Individuals and for clubs with 85 percent of Tier 1 Individuals fully vaccinated. As part of that memo, players and staff were again strongly encouraged to receive one of the approved COVID-19 vaccines when eligible.

Welcome back
Right-hander Domingo Germán will return to the active roster on Thursday, when the Yankees open a four-game series at Cleveland. Germán was optioned to the alternate training site after his most recent outing on April 10, when he allowed four runs and eight hits in four innings to the Rays at Tropicana Field.

“When I went down to the alternate site, I wanted to work on my fastball command,” Germán said through an interpreter. “It’s one of the things I spoke to our pitching coach after my last outing here in the big leagues. I also want to control the different lanes and have my pitches be more effective and sharper.”

Left-hander Jordan Montgomery and right-hander Gerrit Cole are listed as the probable starters for Friday and Saturday, respectively. Sunday’s starter has not been announced.

Bombers bits
• Yankees pitchers entered Wednesday with 181 strikeouts, tied with the 2018 club for the most through the team’s first 16 games in franchise history. The Major League record is 185, shared by the 2018 Astros and the 2020 Reds.

• Aaron Hicks returned to the lineup Wednesday after being held out Tuesday to work on mechanical adjustments. Boone said he was pleased by the patience Hicks showed in his eighth-inning at-bat on Tuesday, helping to set up the decisive frame in the Yanks’ 3-1 victory over the Braves.

This date in Yankees history
April 21, 2012: Trailing by nine runs after the fifth inning, the Yankees rallied for a 15-9 victory over the Red Sox at Fenway Park. Nick Swisher hit a grand slam and Mark Teixeira homered twice in the comeback win.