Pre-summer superlatives: Five surprises from 2018

With summer around the corner and the Monster Energy NASCAR Cup Series taking a week off, it's time to take stock of some of the top surprises to date. Some topics and trends, we expected. Others, not so much.In no particular order, here are five storylines that have raised eyebrows thus far in 2018.

VETERAN RETURN: Matt Kenseth didn't stay away long, coming back to the series with Roush Fenway Racing in a late-April news bombshell. The deal calls for a part-time schedule, splitting time with Trevor Bayne in the No. 6 Ford, but it still stands out as the most prominent personnel change of the season's early going.

BOWYER'S BOUNCE: Clint Bowyer had gone five winless years before breaking back through at Martinsville Speedway in March. Less than three months later, he was back in Victory Lane again, this time at Michigan. Stewart-Haas Racing's 2018 surge overall has made this less of a surprise, but the recent flurry of success stands as a drastic change after going 190 races between wins in his most recent drought.

SEASON OF STREAKS: Before this year, the last time a Monster Energy Series driver had won three straight races was October 2015. This season, it's happened three times already, counting the non-points All-Star Race. Kevin Harvick (left) has accomplished the feat twice (Atlanta-Vegas-Phoenix and Dover-Kansas-All-Star) and Kyle Busch has once (Texas-Bristol-Richmond). Parity has been a common story in recent years, but spurts of uncommon dominance have made the 2018 headlines.

BOWTIE BEREFT: The notion of a learning curve for Chevrolet teams has become a tough reality with the 2018 competition debut of the Camaro ZL1. Chevy hasn't visited Victory Lane since Austin Dillon's triumph in the season-opening Daytona 500 as rival Ford has held the hot hand. Chevrolet still has plenty of star power with Kyle Larson (42) and Jimmie Johnson (48), who will need to fill the surprising void in the season's second half.

BUBBA'S SPEEDWEEKS TO SAVOR: Preseason optimism doesn't always exceed the expectations. So for Bubba Wallace to score a brilliant second-place result in the Daytona 500 with Facebook's docu-series cameras rolling, it equaled a master stroke in just his fifth big-league start.