As the calendar changes to June, the fantasy baseball season enters the all-important summer months. It's during this time that leagues will likely find out which teams will be considered contenders and which teams will be pretenders.
To find themselves in contention, fantasy baseball managers will need to constantly be scouring the waiver wire to land red-hot players or those elevated to a more prominent role. Finding the right player at the right time can be the difference between winning and losing. Several interesting players remain wildly under-rostered in fantasy leagues and managers should grab them while they can.
Three must-add players in fantasy baseball leagues right now

#1 Matt Vierling
Matt Vierling might be the top batter to add right now in leagues for a number of reasons.
The Detroit Tigers outfielder has been red-hot at the plate lately, racking up a whopping nine hits, four home runs and nine RBIs in his last four games. This is the type of player to add and stream for as long as he remains hot.
"Matt Vierling has 3 HR and 11 RBI in his last 6 games" - @MLB
Another reason why Matt Vierling is a must-add player is the fact that he should see an uptick in at-bats. The Detroit Tigers placed Kerry Carpenter on the IL this week, which should lead to additional at-bats for Vierling.
#2 Ryan Weathers
It may be difficult to trust a Miami Marlins pitcher given the team's struggles, but Ryan Weathers has emerged as a legitimate starting option for managers.
Over his last three games, Weathers has thrown 21.0 innings, allowing only a single run, while also racking up 19 strikeouts. He may be viewed more as a temporary option, but his current form might be too much to pass up.
#3 David Fry
Somehow David Fry is still only rostered in 58.9% of ESPN leagues, but this may not be the case for much longer.
The Cleveland Guardians utilityman has outfield, catcher, and first base eligibility in ESPN leagues, which only adds to his appeal. This season, Fry has posted a .353 batting average with 26 runs, seven home runs and 24 RBIs. Get him while you still can.
"David Fry might be the greatest hitter of all time, honestly. #ForTheLand" - @CleGuardians