Assessing Jeff Karstens’s Value

Back on October 1st, the Pittsburgh Post-Gazette reported the Pirates may not tender a contract to Jeff Karstens despite his success in limited action this season. The 30-year-old posted a 3.97 ERA and 3.32 FIP, including an impressive 4.40 K/BB (a career high by nearly a point and a half). But he only made 15 starts and threw just 90.2 innings. He has yet to throw more than 162.1 innings in a season, leading to durability questions:

“He’s doing everything he can to get the best out of his abilities,” [GM Neal] Huntington said. “Unfortunately at times, his body lets him down, and it’s been various body parts.”

Considering the Pirates will have to pay Karstens somewhere around $5 million — he made $3.1 million in his second arbitration season last year — it isn’t surprising nor irrational to see the club mulling nontendering him. Despite his success last season, he doesn’t have a good history — just a 4.44 ERA and 4.55 FIP in 592.1 career innings — and the Pirates are in their usual payroll crunch thanks to the small market.

Most seasons, it probably wouldn’t be worth paying much mind to this situation. But a look at this year’s dreadful free agent class suggests otherwise.

Consider Carlos Villanueva, whom Dave Cameron ranked 24th of his 25 best values of the winter. Villnaueva has just a 4.26 ERA and 4.43 FIP career; he’s coming off a season with a 4.16 ERA and 4.71 FIP, but he had an excellent 3.44 K/BB as a starter and struggles from a home run problem that could be fixed by escaping hitters’ parks like Miller Park and Rogers Centre. And, as Cameron noted, Villanueva’s durability concerns have played a big part in keeping his career from launching. Villanueva set a career high in innings with 125.1 and has repeatedly been pushed to the bullpen over concerns he couldn’t stay healthy as a starter.

Karstens struggled with home run issues much like Villanueva prior to this season, allowing at least 1.0 per nine innings every season and over 1.2 per nine innings all but once. But he has showcased excellent control over the last three years, walking under two batters per nine innings each season. This year, he went to the curveball more often than ever (21 percent) and particularly in two strike counts (30 percent). Karstens’s swinging strike rate jumped from 7.7 percent to 10.4 percent, driving a strikeout rate increase from 14.4 percent of hitters to 17.7 percent.

Part of Karstens’s improvement was a drop to a 7.8 percent HR/FB, his lowest since 2009. But looking at Karstens’s last two seasons, he owns a 3.59 ERA and a 3.94 FIP with a 10.2 percent HR/FB, indistinguishable from his career average. That comes out to a 96 ERA- and a 105 FIP- — in effect, Karstens has been a league average pitcher for 250 innings, and in this market, 100 innings of league average pitching is likely to be worth about $5 million, if not a bit more.

Depending on the Pirates’s finances and how the rest of their offseason shakes up, the uncertainty surrounding Karstens’s durability may make a $5 million payday unreasonable. Perhaps they keep him; perhaps they non-tender him, and a trade may be on the table as well. But looking at what’s available this year, Karstens could be a sneaky value for some team out there, whether it’s in Pittsburgh or elsewhere.