Keeping Bello well rested an ongoing issue

Every time Brayan Bello steps on the field, he gives the Red Sox an exciting glimpse into the future as an effective option in a starting rotation that hasn’t had many this season.

But with every outing — the latest coming in Saturday’s 6-2 loss to Detroit, where Bello pitched 4„ innings — the 24-year-old righthander inches closer to setting a career high in innings. After Saturday’s game, he was at 119‚ innings between the majors and minors, 34 shy of what he threw last year.

The effects of his workload are starting to show. Bello gave up nine hits and four earned runs Saturday, and it was just the fifth time this season he failed to reach the five-inning threshold. In his six starts since the All-Star break, his ERA is 5.71.

“Physically, I bet he’s feeling it, but it’s nothing for us to raise a red flag,” Sox manager Alex Cora said after the game.

“Like you said, it’s a long season,” Bello said, through team interpreter

Carlos Villoria Benitez. “I feel good, I feel healthy, I feel strong, so I just try to make adjustments and try to learn on the go.”

The spin rate on each of Bello’s pitches Saturday fell below their season average, per Baseball Savant. That continues a troubling trend — the spin rate on his primary pitch, the sinker, has dropped precipitously over the course of the season.

“It’s just his second season,” said Cora. “And this guy is very important, not only for now, but for the future. And whenever we have a chance to give him a breather, we will.”

That’s been true even as the Red Sox rotation has been riddled by injuries, forcing the team to piece together bullpen games.

Bello threw 86 pitches in six innings against Seattle on Aug. 1. If he made his next start on “normal” rest — four days between starts — he would’ve pitched in the series finale against Toronto Aug. 6.

But instead, the Sox pushed him back a day and opted for a bullpen game.

The Blue Jays series ended in an emphatic sweep as five Red Sox relievers combined to allow 13 runs in eight innings (Pablo Reyes pitched a scoreless ninth).

The next day, Bello allowed just one run in 6„ innings against the Royals.

“Bello, he’s getting up there [in innings] and I think it made sense for us to push him back,” Cora said of the move.

The Sox have done this throughout the season; 16 of Bello’s 20 starts have come with at least one extra day of rest and he has a 3.39 ERA in those appearances.

When asked to pitch on normal rest — like he was Saturday — that mark balloons to 5.82.

“Nothing really changes, it’s the same routine,” Bello said, when asked about the discrepancy in his performances.

Bello’s most-thrown pitch, the sinker, was put in play seven times vs. the Tigers. Those seven balls in play had an average exit velocity of 95.2 miles per hour, per Baseball Savant — well above the 91.1 he’d allowed off that pitch entering the game.

The number of those scorchers Bello can keep on the ground may dictate his future success.

Between his June 26 and Aug. 1 starts, he had a 5.25 ERA and a groundball rate hovering in the low-60s on the sinker, per Baseball Savant. That shot up to 84.6 percent on Monday, when he pitched to a 1.35 ERA.

In his latest outing, just four of the seven sinkers Detroit put in play were on the ground. Three resulted in outs and one was a single — the other three were line drives that landed for singles.

When asked in early July about potentially reaching the career high, Bello seemed unconcerned. He’d added a pre-game trip to the gym to his daily routine in an effort to keep his body active and the blood flowing.

“As long as you keep your body and your arm in shape, the innings aren’t a worry for me,” Bello said.

As he gets further into his season, the Sox will likely look to keep giving Bello extra days of rest. Cora said Bello’s next start will be Friday against the Yankees, giving him five days of rest.

Getting Bello an extra day of rest will become easier with the return of Chris Sale, and Tanner Houck and Garrett Whitlock close behind.

“Hopefully when guys come back, we can do a few things,” Cora said.

Cora said the team will probably use a bullpen game in the near future — particularly in a late-August series against the matchup-focused Dodgers — to break up the schedule.

“They know it’s 162 and there are days that we’re going to give you an extra day and others that you’ve got to go out there and pitch,” Cora said.

“[Bello is] OK, he’s been trained for this. Obviously, I mean, stuff-wise, I bet the extra day will benefit you, but here where we’re at schedule-wise, he had to pitch on regular rest.”

After a day off Monday, the Red Sox will play 16 games in as many days. They’ll be faced with many issues to address as they continue their hunt for a wild card berth.

Potentially, the most important being how and when to pitch Bello.