Some problems are easy to spot. When a bullpen, let’s say, blows 14 saves in 60 games and has a 7.06 ERA, it doesn’t take a two-time World Series-winning general manager to recognize the need for better relief pitchers.

Diagnosing poor defense isn’t as simple.

The Phillies know they didn’t catch the ball well last season. There were some explanations. Left fielder Andrew McCutchen lost mobility after coming back from knee surgery. Ditto for utilityman Scott Kingery after fighting off COVID-19. Both are expected to be healthier this year.

But questions about the overall team defense lingered into the offseason. Before and after Dave Dombrowski was hired in December to lead baseball operations, the Phillies studied why the infield, in particular, was so porous.

Defensive statistics aren’t always reliable, especially from a 60-game sample. But according to defensive runs saved, a metric created by Baseball Info Solutions, Phillies infielders cost the team 14 runs, 28th out of 30 clubs and nine more runs than in 2019. Based on Statcast’s outs above average, they ranked 21st in the majors.

And the regression was equally apparent by the old-fashioned eye test.

“As a group, we know we need to be better than we were last year,” first baseman Rhys Hoskins said. “There’s no reason to hide from that.”

The Phillies couldn’t if they tried. The infielders’ shortcomings are magnified by the tendencies of the pitching staff. The top three starters — Aaron Nola, Zack Wheeler, and Zach Eflin — and newcomer relievers Archie Bradley, Jose Alvarado, and Brandon Kintzler are extreme ground-ball pitchers. Much of their success will depend on balls not getting through to the outfield grass.

It’s telling that the Phillies didn’t change the personnel. They looked into free-agent shortstop Andrelton Simmons and second baseman Kolten Wong, who have six Gold Gloves between them. Instead, they brought back shortstop Didi Gregorius, a better all-around player than Simmons, and kept Jean Segura at second. Without the designated hitter in the National League, slugging Hoskins and Alec Bohm remain at first and third base.

“There’s a couple moves we could have made if we were going to just improve our defense, but we don’t know if it would have made us a better ballclub,” Dombrowski said by phone last week. “We talked about it a lot. We’re a club that’s going to win some games with our offense and maybe we’ll lose a game with our defense here and there. You give a little bit to get something somewhere else.”

» READ MORE: Dave Dombrowski remade the Phillies' roster in nine weeks. Here's how he did it.

The onus, then, falls on the infielders to get better. But how much improvement can be expected?

Gregorius and Segura will play this season at age 31. Each has nine years of major-league experience. If anything, their skills are eroding. Hoskins’s bat has always been stronger than his glove. And some rival evaluators have long questioned whether Bohm, at 6-foot-5, has the agility to stick at third base.

“One thing we’ve talked about is trying to increase the range of our infield,” manager Joe Girardi said. “That’s one of our focuses in spring training, to improve that area.”

Infield coach Juan Castro is leading the effort. He meets the infielders each morning at the half-field that abuts the team’s complex. Along with Larry Bowa and former New York Yankees infielder Bobby Meacham, a coaching assistant on Girardi’s staff, Castro has implemented new drills to help improve agility, footwork, and first-step quickness.

Mostly, though, Castro is stressing what he calls “pre-pitch,” the actions that an infielder must take to be as ready as possible when the ball is hit. Think of a tennis match and you get the idea.

“When a guy is serving, the other guy is waiting and kind of moving, getting ready, so by the time the [server] hits the tennis ball, he’s in a ready position to move anywhere,” Castro said. “It’s kind of the same for infielders. I believe if an infielder is ready to move by the time of contact, they have more chance to react and get to a ball that they wouldn’t get to if they’re late.”

Sounds elemental, right? But Castro noted that infielders must pay attention to the type of pitch that is about to be thrown and the tendencies of the hitter at the plate. It all factors into their positioning, which influences their anticipation and therefore their ability to get to more balls even if their physical skills don’t change.

And they must maintain that focus for nine innings. For whatever reason — Castro suspects it had to do with the absence of fans — Phillies infielders had too many concentration lapses last season.

» READ MORE: Didi Gregorius set to arrive in Phillies camp after visa delay

Take Gregorius, for example. Dombrowski characterized his range as “not one of the better ones in the league, but he catches what he gets to.” And Castro believes Gregorius will get to more balls “if he gets engaged like he can on the field every [pitch].”

“You can ask Segura,” Castro said. “I was on his tail all the time last year like, ‘Come on, man. You need to be more ready. Your pre-pitch needs to be better.’ Larry Bowa says that when you finish a game, you should be tired mentally as an infielder because constantly you’re doing pre-pitch. I know they’re going to listen and they’re going to continue to work.”

Said Hoskins: “There’s little things that are being stressed, pre-pitch stuff, making sure we know where we’re going with the ball before each pitch. Just going through those fundamentally sound things that often get overlooked.”

Segura, a shortstop for most of his career, figures to benefit from staying at second base. He began last season at third, then moved to second after Bohm was called up Aug. 13.

Bohm has the most room for growth, considering his defense has continued to improve since the Phillies drafted him in 2018. Third base requires quick reaction time, but Castro said Bohm is also learning to slow his body and not rush throws after making an initial play on a ball.

“I love this kid, the passion that he has to be better,” Castro said. “He gets mad when he doesn’t do things the right way. This kid is going to get better.”

Perhaps the same could have been said for the Phillies’ overall infield defense last season. Given another 100 games, the performance might have stabilized. Or maybe not.

» READ MORE: Alec Bohm's defense is another reason to look forward to his second season with the Phillies | Bob Brookover

Regardless, better defense will be as important to run prevention as recasting that horrid bullpen.

“If we do a good job in our positioning, if we do a good job on pre-pitch, definitely we’re going to be better than last year,” Castro said. “I’m hoping they get better a lot. But even if they get a little better, it’s a win.”