(CBS) Powerful agent Scott Boras is preaching the merits of Cubs right-hander Jake Arrieta as he endures an uneven start to this season with free agency awaiting in November.

Choosing to view Arrieta’s accomplishments through a three-year window instead of just 2017, Boras believes Arrieta has outperformed Nationals right-hander Max Scherzer and Red Sox left-hander David Price, a pair of aces who signed massive deals in recent years.

Scherzer signed a seven-year, $210-million deal with the Nationals in January 2015 when he was 30 years old. Price signed a seven-year, $217-million deal with the Red Sox in December 2015 when he was 30.

“Scherzer has been good,” Boras told Fan Rag Sports’ Jon Heyman. “But not to the level of Arrieta.”

Boras also called Arrieta “better than Price” while touting his postseason accomplishments as being crucial.

“He has a three-plus-year history of dominance,” Boras told Heyman. “Of all the pitchers – David Price, Zack Greinke and Max Scherzer – he was the best over a three-year period.”

Arrieta had historic 2015 season, winning the NL Cy Young while going 22-6 with a 1.77 ERA and 0.87 WHIP. He was 18-8 with a 3.10 ERA and 1.08 WHIP in 2016, but this season has seen an even more worrisome dip in performance. Arrieta is 5-4 with a 4.60 ERA and 1.34 WHIP while seeing a velocity dip. He’s still striking out a career-best 10.2 batters per nine innings, but he’s also allowing a career-worst 1.6 homers per nine innings.

The lack of consistency has led to worry about the 31-year-old Arrieta’s reliability as he approaches free agency.

Arrieta has a cumulative 2.67 ERA since the start of the 2015 season. Scherzer has a cumulative 2.83 ERA since 2015 began, and he when he signed his mega-deal he was coming off a 2014 season in which he went 18-5 with a 3.15 ERA and 1.18 WHIP.

When Price signed his lucrative deal with the Red Sox, he was coming off a 2015 season in which he was 18-5 with an AL-best 2.45 ERA and finished second in the Cy Young voting.