The MLB trade deadline was extremely active, and may have changed your fantasy baseball team. But with the regular season winding down, you have to make sure you have the best possible roster for this week's matchup. The fantasy baseball waiver wire will be active up until the playoffs, so make sure you get your moves in soon.

Each of the players on our list is claimed in fewer than half of ESPN fantasy baseball leagues. From starting pitchers to hitters who can change your lineup, your team could use these upgrades. Most leagues end their regular season at the end of August, so you only have three matchups left. This one is important, and these players should be on your team.

Fantasy baseball waiver wire pickups for Week 20

Chicago White Sox center fielder Luis Robert Jr. (88) hits a home run against the Seattle Mariners during the ninth inning at T-Mobile Park.
Steven Bisig-Imagn Images

Luis Robert Jr, Chicago White Sox OF (Rostered: 28.9%)

There were a lot of rumors that the White Sox would trade Robert before the July 31 deadline. Instead, they kept the outfielder and are rumored to be picking up his $20 million option for next season. But since the All-Star Break, Robert has been sensational and can improve your lineup.

Since the break, Robert is hitting .383 with a 1.019 OPS and 11 RBI. He has kept up his incredible base running as well, with seven stolen bases in those 13 games. It makes sense why fantasy baseball managers have stayed away from Robert this season, but he is heating up and should be on your roster.

Jeffery Springs, Athletics SP (Rostered: 24.2%)

The Athletics are out of playoff contention, but they still have some good players worth picking up in fantasy baseball. Most of them are hitters, but Jeffery Springs has been solid on the mound this year. With starts against the Tampa Bay Rays and Los Angeles Angels on deck this week, he is the streaming pitcher of the week.

Springs has a 4.o0 ERA in 23 appearances, and has actually been slightly better at home. While the rest of the Athletics' pitching staff has struggled in Sacramento, Springs has a 3.99 ERA in 1o appearances there. Neither of the offenses on tap is extremely strong, which should help his numbers for fantasy managers in this important matchup.

Adrian Houser, Tampa Bay SP (Rostered: 22.6%)

Houser will likely only make one start this week, but he is worth a pickup for the stretch run. He was curiously acquired by the Tampa Bay Rays at the MLB trade deadline and had his first horrific start of the season in his team debut. But with his next start likely coming on the road against the San Francisco Giants, now is the time to snag him.

Not only are the Giants tumbling out of the playoff picture, but they play in a pitcher-friendly park. Houser should bounce back in that start, even if he does not on Sunday against the Mariners. Houser has been incredible this year, but toiling away on the White Sox was not getting him fantasy baseball buzz. If the Rays are going to get in the race, Houser will be a reason why.

Warming Bernabel, Colorado 1b/3b (Rostered: 20.1%)

The Colorado Rockies traded away a few of their players before the MLB trade deadline, continuing a dreadful season. But when they replenished the roster from the minors, they called up Warming Bernabel. Since making his debut on July 26, he is hitting .400 with a 1.190 OPS. If you are looking for positional versatility in your infield, Bernabel can be your guy down the stretch.

The Rockies are playing for nothing, outside of avoiding the record for most losses in a season. They should give all of their young players run down the stretch, including Bernabel. With that in mind and his incredible numbers to start, give him a shot in fantasy baseball. He may be the difference in your playoff race.

Ceddanne Rafaela, Boston SS/OF (Rostered: 46.5%)

The Boston Red Sox have been one of the hottest teams in the league in recent weeks. They have jumped into the top AL Wild Card spot and are challenging the Toronto Blue Jays for the AL East lead. Ceddanne Rafaela has been amazing all season long, and they have prioritized his defense in the outfield with their roster moves. Rafaela will be in the lineup, and he will help your fantasy baseball lineup.

Since July 1, Rafaela is hitting .301 with an .861 OPS and 18 RBI. He has been a key cog to their offensive surge and is dynamic in the field. The latter won't help your team, but it will guarantee him at-bats down the stretch.