The National League East entered the year with the expectation that it would be the most exciting and competitive division in the Major Leagues. It has certainly been compelling through the first half of the season, even though the Braves have raced out to a six-game lead over the second-place Nationals at the unofficial halfway point, with the Phillies trailing just behind at 6 1/2 games.

Those top three teams still hold high playoff aspirations and will be looking to gear up for a potential stretch run. The other two clubs, the Marlins and Mets, will have pieces to potentially trade away that could cause a huge impact in a possible playoff race. With the Trade Deadline coming up on July 31, here is one player to watch who could affect how each of the five teams approach the end of the month:

Braves
Player to watch: Luke Jackson
The next few weeks give the Braves an opportunity to determine whether they are comfortable with Jackson as their closer or if they need to look for a veteran for a potential postseason push. Jackson owns a 2.66 ERA with 59 strikeouts and 15 walks in 40 games, but he is 14-for-20 in save opportunities this year. Jackson has been pretty good in his last nine appearances, but over the next few weeks, Atlanta will have to decide whether it can count on him with the game on the line down the stretch and beyond.

Marlins
Player to watch: Sergio Romo
There is no shortage of teams around the league in need of bullpen help, and the Marlins should be motivated to move Romo, who is on a one-year deal and has been solid throughout the first half. He has converted 16 of his 17 save opportunities, with a 4.13 ERA, 27 strikeouts and 13 walks. The veteran Romo, who has playoff experience and has won three World Series, could be a flexible bullpen arm for a contending team considering his experience pitching in roles ranging from opening to closing.

Mets
Player to watch: Zack Wheeler
The best right-handed starting pitcher available this month is Wheeler. He and Giants lefty Madison Bumgarner will be the top starters projected to be on the move. Wheeler has been settling into a groove recently, and aside from a rocky outing just before the break, he completed a three-start stretch where he put up a 1.86 ERA. If Wheeler can continue to show teams that he is still capable of putting together a string of outings similar to his last 12 starts of 2018, the Mets could land a nice prospect package before he hits free agency.

Nationals
Player to watch: Fernando Rodney
The Nationals need bullpen help. Their relievers have been the team’s biggest flaw all season long, entering the break with a 6.08 ERA, the worst in the league. Aside from Sean Doolittle, the Nats are struggling to close out games. They will almost certainly need to add to that group this month, but perhaps Rodney has something left in his arm. Despite getting released by Oakland earlier this year, Washington manager Dave Martinez has inserted Rodney into high-leverage situations, so far with success -- two runs in 5 1/3 innings, with six strikeouts, one walk and a pair of saves converted while Doolittle was unavailable. If Rodney can continue to be an effective late-inning reliever, he could be a huge boost for the Nats. If his small sample size doesn't hold up, they probably need two relievers instead of one.

Phillies
Player to watch: Jake Arrieta
Arrieta has a bone spur in his right elbow, but Phillies manager Gabe Kapler told a Philly radio station on Wednesday morning that Arrieta will pitch through it. He is still scheduled to start this weekend against the Nationals, but his injury puts an even greater emphasis on the Phils’ starting rotation, an already glaring weakness they were going to have to address before the end of the month. They probably need another starter anyway, but if this is something that Arrieta can’t pitch through, because of surgery or ineffectiveness, it makes it even more critical for Philadelphia to make a move before July 31.