AaronGleeman.com

Twins starting pitchers combined for a 5.00 ERA during the past two seasons to rank dead last in the league and they head into the offseason with only Scott Diamond locked into a rotation spot. Terry Ryan has said he'd prefer to address the rotation via trades, which is no surprise for a team that's basically never pursued free agent pitching beyond bargain-bin shopping, but if they do decide to dive into the free agent pitching pool the water is reasonably deep.

In an effort to figure out the Twins' options I've separated the free agent pitching class into three categories: Top-of-the-rotation starters, middle-of-the-rotation starters, and back-of-the-rotation starters. Below are the back-of-the-rotation starters, which I view as a No. 4 or No. 5 starter on a contending team and a group the Twins hopefully won't be looking to overspend on in the name of simply adding veterans regardless of upside.

• Joe Saunders - LHP - 175 innings - 4.07 ERA - 4.25 xFIP - 112/39 K/BB

Kansas City saved the Twins from Jeremy Guthrie, but Saunders is a similar mix of durable mediocrity and lots of pitching to contact. Toss in the fact that he avoided getting knocked around in a pair of playoff starts and he's a name to watch as a potential overspend. Saunders would be a perfectly decent one-year pickup, but among the 113 starters with 500-plus innings since 2008 he's 104th in strikeout rate and 100th in xFIP, one spot ahead of Nick Blackburn.

• Scott Feldman - RHP - 124 innings - 5.09 ERA - 3.87 xFIP - 96/32 K/BB

Run support and luck allowed Feldman to win 17 games in 2009 despite a 4.08 ERA, but in three seasons since then he's been ineffective and injured with a 5.15 ERA in 297 innings. His secondary numbers this year were actually pretty good, but for a 6-foot-6 guy with above-average velocity he's never generated many strikeouts. And while he's done half his pitching in Texas' hitter-friendly ballpark Feldman's numbers on the road haven't been any better.

• Roberto Hernandez - RHP - 14 innings - 7.53 ERA - 5.39 xFIP - 2/3 K/BB

Formerly known as "Fausto Carmona" before getting busted for a false identity last winter, Hernandez missed the first four months and was then shut down after three starts with an ankle injury. Once upon a time Hernandez was a very promising young pitcher, but it turns out he was never actually all that young and since 2008 his ERA is 5.06. His ability to induce ground balls is intriguing, but Hernandez doesn't miss many bats and has always had awful control.

• Jeff Francis - LHP - 113 innings - 5.58 ERA - 4.07 xFIP - 76/22 K/BB

Francis broke into the big leagues throwing in the high-80s and the No. 9 overall pick in the 2002 draft had plenty of early success, but shoulder problems have left him working in the mid-80s and the results haven't been pretty. He's adapted by becoming an extreme strike-thrower, trailing only Cliff Lee for the best walk rate among left-handed starters since 2010, but there's very little upside attached to Francis at this point.

• Jason Marquis - RHP - 128 innings - 5.22 ERA - 4.03 xFIP - 91/42 K/BB

Marquis signed a one-year, $3 million deal with the Twins last offseason and was as bad as a pitcher can be, posting an 8.47 ERA with more walks than strikeouts. They released him after seven starts and Marquis quickly landed in San Diego, where he was the guy the Twins thought they were signing with a 4.05 ERA and 79/28 K/BB ratio in 94 innings before breaking his hand. I wasn't very enthused by the Marquis acquisition back then and suffice it to say a sequel is unlikely.

• Kevin Millwood - RHP - 161 innings - 4.25 ERA - 4.42 xFIP - 107/56 K/BB

Millwood is exactly the type of veteran, low-upside free agent pitcher the Twins have pursued in offseasons past. He looked finished after a terrible 2010, but has thrown 215 innings with a 4.18 ERA since then and at age 37 his strikeout rate remained reasonably close to his career norms. If he were one of the Twins' primary additions it would be a disastrous offseason, but as a cheap one-year stop gap at the back of the rotation Millwood wouldn't be the worst idea.

• Kevin Correia - RHP - 171 innings - 4.21 ERA - 4.34 xFIP - 89/46 K/BB

Correia was an All-Star in 2011, which is pretty funny considering he finished that season with a 4.79 ERA and has a 4.54 career mark. That includes a 4.49 ERA for the Pirates during the past two seasons and Correia's once-decent strikeout rate plummeted to 4.6 per nine innings over that span for the lowest rate in baseball among right-handed starters. He doesn't miss bats, doesn't induce a ton of ground balls, and doesn't have great control.

• Freddy Garcia - RHP - 107 innings - 5.20 ERA - 4.06 xFIP - 89/35 K/BB

After an excellent start to his career Garcia looked finished at age 31, but he's stuck around into his mid-30s by re-inventing himself as a slop-thrower. His fastball has averaged just 87 miles per hour during the past three seasons, yet over that span Garcia has a 4.42 ERA in 411 innings and his 7.5 strikeouts per nine innings this year was his highest rate since 2007. Much like Millwood he has zero upside, but as cheap stop-gap options go he'd fit as a fifth starter.

• Chris Young - RHP - 115 innings - 4.15 ERA - 5.36 xFIP - 80/36 K/BB

Young has basically never been healthy, topping 175 innings once in nine years, but after missing most of 2009-2011 he came back to make 20 decent starts for the Mets. His average fastball clocked in at 85 miles per hour, which doesn't fit his 6-foot-10 frame, but even at his peak Young worked in the high-80s. Despite all the injuries Young has a 3.79 career ERA and more upside than Millwood or Garcia, but that isn't really saying much and a fragile fifth starter isn't ideal.

• Carl Pavano - RHP - 63 innings - 6.00 ERA - 4.48 xFIP - 33/8 K/BB

Pavano tried to pitch through a shoulder injury with disastrous results, spent the final four months on the disabled list, and took some veiled shots at the Twins' medical staff on his way out the door. That doesn't necessarily rule out a return to Minnesota, but Pavano's velocity and strikeout rates were worrisome even before the arm problems derailed him and at age 36 he looks like a potential stop gap fifth starter at best.

• Carlos Zambrano - RHP - 132 innings - 4.49 ERA - 4.84 xFIP - 95/75 K/BB

It's hard to imagine Zambrano being worth the trouble at this point. He's still just 31 years old, but heavy workloads from early in his career mean it's an old 31 and Zambrano's velocity and strikeout rate are free falling. He issued a career-high 5.1 walks per nine innings and while that wildness may have helped him remain relatively tough to hit Zambrano had a 7.62 ERA with more walks (38) than strikeouts (27) in his final nine starts before a demotion to the bullpen.

• Derek Lowe - RHP - 143 innings - 5.11 ERA - 4.59 xFIP - 55/51 K/BB

Lowe has always been a pitch-to-contact, ground-ball guy, but his strikeout rate reached comically low levels at age 39. He was traded by the Braves, released by the Indians, and relegated to bullpen duties by the Yankees, so he's clearly running on fumes. However, he did still manage the second-highest ground-ball rate in all of baseball at 59 percent and that alone makes Lowe a potentially useful fifth starter if he's not totally washed up.