ATLANTA -- New blood can change the feel and dynamic of a team, both on the field and in the clubhouse.
There are plenty of new faces in the National League East. Some of them have had a major impact on their team's success the first three weeks of the season. Others have not. Here is a look at some of the most notable newcomers in the NL East entering Thursday:
Braves
Who's the new guy? Outfielder Preston Tucker
How's it going so far? Tucker has been taking advantage of his opportunities in left field as top prospect Ronald Acuna plays in Triple-A. Tucker entered Thursday with 13 hits, including two doubles and three home runs, in 53 plate appearances. He has posted an .821 OPS as Atlanta's lineup scored runs in bunches early.

What's on deck? Many people expected Acuna to join the team this week, but he has struggled early. He could remain with Gwinnett until he shows consistent results. In the meantime, Tucker will continue to play. After that, he is expected to strengthen the Braves' bench.
Number to know: 92.6. Tucker's average exit velocity of balls in play ranks 23rd out of 204 batters (minimum 30 balls in play).
Marlins
Who's the new guy? Outfielder Lewis Brinson
How's it going so far? Brinson joined the organization in the offseason as a key piece in the Christian Yelich deal with Milwaukee. He hit .280 (7-for-25) through Miami's first five games, but he is just 1-for-36 in 11 games since. Marlins manager Don Mattingly gave him a break this week in New York to work on his swing in the batting cage.
What's on deck? Brinson eventually will have to show some improvement at the plate or he could be optioned to Triple-A, where there will be less pressure to perform and more opportunities to work on his adjustments. But Brinson is Miami'sNo. 1 prospect for a reason. The Marlins believe he will get rolling at some point.
Number to know: 15 -- the number of Brinson's strikeouts in 36 at-bats during the 11-game skid.
Mets
Who's the new guy? Third baseman Todd Frazier
How's it going so far? Frazier signed a two-year, $17 million contract just a few days before Spring Training. The early returns have been phenomenal, posting a .929 OPS in 73 plate appearances. Frazier not only has been a force in the Mets' lineup, but he has been solid defensively at third base and aggressive on the basepaths. Frazier has emerged as a clubhouse leader, too. He even invented the "salt and pepper shaker" celebration. Bonus points for that? Sure, why not?

What's on deck? It will be interesting to see if Frazier can maintain this pace offensively. He averaged a .774 OPS the previous five seasons, following a career-best .829 OPS with the Reds in 2012. If Frazier replicates his '12 success or even exceeds it, the Mets will have one of the best bargains of the offseason.
Number to know: 15. Frazier entered the year with 819 strikeouts and 336 walks in his career. He entered Thursday with 15 walks and 17 strikeouts.
Nationals
Who's the new guy? Manager Dave Martinez
How's it going so far? Martinez has not been in the spotlight much these first couple weeks, which generally is a good thing for a rookie manager. He has, however, drawn endorsements from his players, which is a good thing. "We have a manager in there who believes in us," Bryce Harper said earlier this week.
What's on deck? The Nationals have started slowly, and it is Martinez's job to get them going, injuries or not. Rightly so, Martinez has not panicked and has remained upbeat, trusting that a veteran team familiar with winning knows how to navigate itself through a rough patch.
Number to know: 3.38. Washington's starters rank eighth in the Majors with a 3.38 ERA. If that number holds, the Nats should start winning some games in the near future.
Phillies
Who's the new guy? Starting pitcher Jacob Arrieta
How's it going so far? Arrieta will make his third start of the season Thursday against the Pirates. His first two starts have gone well. Since Arrieta allowed two earned runs in his first inning in his first start April 8 against the Marlins, he has 1.86 ERA in 9 2/3 innings. He has allowed seven hits, two earned runs and one walk in that stretch. Arrieta has struck out six.

What's on deck? One of the reasons Arrieta did not sign until March 12 is that teams had concerns about a dip in performance since he won the NL Cy Young Award in 2015. A few more solid starts in the coming weeks should make the Phillies feel more comfortable about his three-year, $75 million contract.
Number to know: 91.8. Arrieta's fastball velocity has been a focus the past few seasons. It is averaging 91.8 mph through two starts, which is a slight decline from last season (92.2 mph).