There were many impressive performances in the first half of the season that led to appearances in Tuesday’s All-Star Game in Cleveland.

Now that the MLB schedule is resuming, with the Astros and Rangers playing on Thursday night and the other 28 clubs following Friday, those responsible for 2019's eye-popping numbers will set about trying to maintain their success. That’s no easy feat in this humbling game, and it’s folly to assume most players will replicate their pre-break output.

Still, it’s worth taking a look at the quick pace some of these stars have set, and where it could lead should they beat the odds and finish as fast as they have started.

With that in mind, here are 10 numbers to watch in the second half:

Alonso’s home runs (162-game pace: 54)

Mets rookie first baseman Pete Alonso has emerged as one of the game’s top sluggers, as he showed in Monday’s Home Run Derby. Alonso mashed 57 total home runs in the event and defeated Vladimir Guerrero Jr. in a heart-racing final round, joining Aaron Judge as the only rookie champions in Derby history.

That’s fitting, because “Polar Bear” Pete also is chasing another Judge record. Alonso already joined Judge (2017) and Mark McGwire (1987) as the only rookies to launch 30 home runs before the All-Star break, and Judge’s rookie record of 52 total dingers is within reach. Barring injury, Cody Bellinger’s 2017 mark of 39 for an NL rookie should be an easy target.

Bellinger’s WAR (162-game pace: 11.6)

It’s difficult to find enough superlatives to describe Cody Bellinger's 2019 season thus far. The National League MVP Award frontrunner is dominating in every facet of the game, contributing to his MLB-high first-half total of 6.6 WAR, per Baseball Reference.

While Bellinger surely will have a difficult time maintaining that pace, he has a chance to become only the 28th position player to crack the 10-WAR plateau, and the fourth active player, after Mookie Betts, Bryce Harper and Mike Trout. Just six NL position players have accomplished the feat in the past 70 years: Harper, Barry Bonds, Sammy Sosa, Joe Morgan, Willie Mays, and Ernie Banks.

Trout’s career WAR (162-game pace: 74.7)

Watching Mike Trout's rapid ascent up the career WAR chart is a jaw-dropping annual pastime. By leading the AL with 5.9 WAR before the break, Trout breached the 70-WAR barrier for his career ahead of his 28th birthday, which is coming up on Aug. 7. He is the 69th position player in MLB history to get there (Miguel Cabrera soon could be No. 70).

Not only is Trout on pace to join Babe Ruth, Willie Mays and Rogers Hornsby as the only position players with at last four 10-WAR seasons, but he also has a shot to get to 75 career WAR before the end of 2019. He would be the 50th position player to do so, and would pass the likes of Barry Larkin, Derek Jeter, Jim Thome, Frank Thomas, and Reggie Jackson.

Ryu’s ERA+ (162-game pace: 241)

The NL’s starter in the All-Star Game, Hyun-Jin Ryu entered the break with a 1.73 ERA that would be 1.20 without a rough start at Coors Field on June 28. That translates to a 241 ERA+, a stat that adjusts for ballpark and league environment, and for which 100 is average.

At this point, Ryu’s ERA+ is the best since Pedro Martinez’s absurd 291 in 2000, which also was the last time any pitcher topped 230. Only 10 qualified pitchers in the past 40 years have cracked the 200 mark, including Cy Young Award winners Jacob deGrom and Blake Snell in 2018.

Yelich’s homers and steals (162-game pace: 55-34)

Who had a better past 365 days, entering the All-Star break, than Christian Yelich? In 156 games since last July 8, the 2018 NL MVP is batting an incredible .348/.438/.717 (a 194 wRC+) with 56 home runs, and 31 stolen bases. It’s one of the most impressive “seasons” in baseball history -- even if it’s not technically one season.

Can Yelich keep it going for another half? If so, he might finish 2019 with a similar 50-30 combo. While four players have gone 40-40, and nine have gone 40-30, none has gone 50-30. Larry Walker has the record for most homers in a 30-steal season (49 in 1997), while Alex Rodriguez (2007) and Willie Mays (1955) have the most steals in a 50-homer campaign, both with 24.

Scherzer’s strikeouts (162-game pace: 329)

He will turn 35 on July 27 but shows no signs of slowing down. A year after finishing with exactly 300 Ks, Max Scherzer has an MLB-high 181 this year. Ranking second in the Majors in both innings and strikeout rate, Scherzer has the stamina and stuff to become the first pitcher since Randy Johnson (1998-2002) to reach 300 in back-to-back seasons.

If Scherzer can keep the Ks coming down the stretch, he’d be the first pitcher since Curt Schilling in 2002 to get to 310 in a season. Since the mound was lowered after 1968, Hall of Famers Johnson and Nolan Ryan are the only pitchers ever to reach the 320 mark.

Cole’s strikeout rate (162-game pace: 36.7%)

The only pitcher with a higher strikeout rate than Scherzer (35.2%) this season is Gerrit Cole. And not only that, but the Astros right-hander currently has the third-best single-season rate for a qualified pitcher in baseball history, trailing only Martinez in 1999 (37.5%) and Johnson in 2001 (37.4%).

True, this is a strikeout-heavy era. But Cole, who struck out 34.5% of batters in his Houston debut last year, has been unquestionably overpowering, with nine double-digit strikeout games.

Bell’s extra-base hits (162-game pace: 109)

With 30 doubles, 27 home runs and three triples, Josh Bell became only the ninth player in MLB history to reach 60 extra-base hits by the All-Star break, and the first since Chris Davis in 2013. It was all part of a breakout first-half performance for the switch-hitter, whose previous high for an entire season was 58 in ‘17.

Should Bell keep barreling the ball, he could become only the 16th player to reach 100 extra-base hits in a year, and the first since Barry Bonds, Luis Gonzalez, Todd Helton and Sammy Sosa all did it in 2001. Only Ruth (119 in 1921) and Lou Gehrig (117 in ‘27) have topped 107.

Acuña’s home runs (162-game pace: 37)

Ronald Acuña Jr. is just 21 years old and owns a .901 career OPS and 47 homers -- 26 as a rookie and 21 so far this year. And they haven’t been cheap, as he ranks in the top five in both average exit velocity (108.2 mph) and distance (421 feet) on homers in 2019, among those with 10 or more.

Soon, Acuña will become just the eighth player to have multiple 25-homer seasons through age 21. A total of 37 this year would get him to 63 for his career. The only players with 60-plus homers by the end of their age-21 seasons are Mel Ott (88), Tony Conigliaro (84), Eddie Mathews (72), Frank Robinson (67), Rodriguez (64), Trout (62), and Ken Griffey Jr. (60).

Minnesota Twins home runs (162-game pace: 302)

With home runs up across the game, MLB as a whole is on pace to produce 6,668 of them, smashing the single-season record of 6,105 set just two years ago. And four teams -- the Twins, Mariners, Brewers and Yankees -- are on pace to surpass the 2018 Yankees’ record total of 267.

But Minnesota is well ahead of the pack, building a 5 1/2-game AL Central lead behind a robust offense that has gone deep 166 times in 89 games, or 1.87 times per game. While the Twins don’t have anyone in the top 10 in MLB in homers, they have 10 different hitters who already have reached double digits, with Byron Buxton (nine) poised to become No. 11. Just six teams have ever had 11 players homer 10-plus times in an entire season.