One morning in late June, Caleb Walls was taking advantage of a rare opportunity to sleep in when his phone rang, startling him awake.

Walls’ junior college coach, Lyndon Coleman, was on the other end.

“Hey, I just got off the phone with a Maryland coach,” Coleman told him. “He should be calling you soon.”

The next thing Walls knew, he was talking to Maryland baseball assistant coach Corey Muscara. The Terps had lost two outfield starters and two outfield recruits from 2018, so they needed a late addition to the roster.

Walls didn’t hesitate.

“I’m your guy,” he said.

After a debilitating back injury sidelined him for months and eventually led to his transfer from George Mason to Pasco Hernando State College, Walls was finally getting the chance to return to Division I baseball. Now, his team says the determination that allowed him to become a Terp makes him their ideal leadoff hitter.

“He’s just a gamer,” Terps coach Rob Vaughn said. “He’s not the fastest, he doesn’t have the most power, his tools don’t just completely jump off the page, but he’s just a gritty baseball player.”

[Read more: Maryland baseball used a plethora of pitchers during its opening weekend]

Before the 2017 season, Walls suffered a back injury that kept him practically bedridden for six months. It changed the course of his career but allowing him to gain new perspectives on baseball, his surroundings and himself.

The recovery process was rocky, he said, and while spending his sophomore season learning to pick up on how opposing pitchers tip their pitches, Walls also realized George Mason wasn’t the right fit for him.

“It’s tough when you get told you can’t play,” Walls said. “You just have to watch your best friends go out there and play the game you love. But it definitely helped me to be a lot tougher, [learn to] overcome adversity and just fight through things that you think you can’t fight through.”

[Read more: Maryland baseball tops VCU, 5-3, for first win of 2019]

Once Walls could return to the field, he joined a summer team in the Valley Baseball League, where Coleman first spotted him.

Walls stood out before the game even began, Coleman said. Other players casually walked onto the field, but Walls ran — everywhere. From the outfield fence to the dugout, and then back out to stretch, which he followed with sprints.

“While everybody else was just hanging out, waiting for the game to start,” Coleman said, “he’s preparing like it’s the last game he’s ever played.”

Coleman wondered whether this was part of Walls’ routine, or if he was just putting on a show to impress coaches in the stands.

He approached Walls’ coach to find out. The response was firm: “He does it every single time.”

And when Walls joined Coleman at Pasco Hernando in New Port Richey, Florida, he brought that work ethic with him.

Determined to gain back the weight he lost due to injury, Walls hit the weight room at least four times a week. He practically lived at the batting cage and fielded fly ball after fly ball on the field.

When Vaughn first saw Walls the following summer, he had the same impression as Coleman. And once Walls visited to College Park, the coaches were sold, believing Walls’ humility and nose-to-the-grindstone attitude epitomized the mentality they look for in recruits.

Sure enough, Walls spent the offseason overhauling his swing with hitting coach Matt Swope, preparing for the highest level of college baseball he’s played with the same mentality he showed when attacking his back injury.

Vaughn said he put Walls at the top of the lineup due to his toughness as much as his ability to get on base, but regardless of the reason, the decision paid off over opening weekend.

Walls singled in his first at-bat and hammered a solo home run — ”He’s got some sneaky power in there,” Vaughn said — in his second. He finished the weekend 4-for-11, took three walks and scored four runs.

And when the Terps got back to campus, Walls went right back to work on their off-day.

“He’s always on the field,” right-hander Trevor LaBonte said. “He was in the shell for several hours on Monday, just doing his thing.”

For Walls, it’s just about taking advantage of the second chance it wasn’t always clear he would get.

“It’s been a little crazy, I’ve bounced around a bit,” Walls said. “To have an opportunity to play with this group of guys — for these coaches, for coach Vaughn — it’s just a once-in-a-lifetime experience.”