When former UMBC head coach Randy Monroe resigned just one month before last season, Aki Thomas had to fill the vacancy with an interim label.

But Thomas impressed Charles Brown so much in 2012-13 that the director of athletics removed the interim tag, naming the former Howard standout the program’s head coach after he doubled the Retrievers’ win total and staged an upset of third-seeded Hartford in the America East quarterfinals.

Of course, this was all done with the help of Ryan Cook, the league’s third-best scorer. The former Retriever scored 15.4 points per game and ranked fifth in the league with a 38.5 percent clip from long range.

But Cook — a pro with OKK Sloboda Tuzla in the Bosnian Liga I — and sharpshooter Brian Neller are no longer with the program after exhausting their eligibility last season.

“You can’t really replace a veteran scorer like [Cook] with just a player, sometimes not even two players. It has to be done collectively as a team,” Thomas said. “A veteran scorer like Cook, and Brian Neller — those guys are really invaluable. It takes time to become that kind of player at the college level, and they had the time to do that.”

As a team, Thomas hopes to mitigate the losses of Cook and Neller by strengthening a defense that ranked last in the America East with 71.5 points allowed per game in 2012-13.

“We really want to be able to get more stops on the defensive end than we’ve got in the past,” Thomas said, “and I think that’s going to be the biggest difference for the team from last year.”

Senior forward Chase Plummer should provide some of that defensive security. The three-year captain ranked seventh in the conference in rebounding last season with 6.4 per game, 11th in scoring with 11.8 points per game and second in steals, with 1.7 per game, all en route to earning all-conference second-team honors.

After fracturing a cheekbone and missing the final 12 games of the season, classmate Brett Roseboro will also be an integral component of the Retrievers’ defense. After transferring from St. Bonaventure after the 2010-11 season, Roseboro debuted for UMBC last year with 49.1 percent shooting and 6.3 rebounds per game.

“Those two guys are proven interior players in our league … and we’re looking for both of those guys to contribute on the inside, in rebounding and defensively. Especially defensively,” Thomas said. “Chase brings a level of offensive prowess to that position, and Brett is really one of the dominant defenders of our league interior-wise, being able to change shots and rebound the ball.”

Junior guard Joey Getz will return as well. A year after averaging 5.8 points per game, Getz will have an expanded role in the offense.

“He’s definitely talented and has the ability to [fill Cook’s role],” Thomas said. “I think this should be a coming out year, so to speak, for Joey.”

For the rest of their offense, Thomas will rely on some new faces, including freshman guards Will Darley and Rodney Elliott. Darley averaged 21 points and seven rebounds per game his senior year of high school, while Elliott led his team with 16.6 points, 4.2 rebounds, 3.6 assists and 1.3 steals a contest during his.

“Elliott’s, of course, a point guard and we need help in that position,” Thomas said. “Will Darley we’ll need; he’s a really good shooter, he’s an outside threat. We lost a lot of that in Brian Neller and Ryan Cook, so we’ll need shooting and [Darley’s] done a really tremendous job so far in practice.”

So how high can the Retrievers jump this year?

“[That’s] still up in the air. We’re really half returners and half new guys on the team,” Thomas said. “It’s going to come down to our chemistry and how we gel and how quickly that happens to determine the kind of success we can have this year.”