Daniel Clark: O's rotation set for change

As the Orioles continue to experience troubles on the mound, a series of injuries last week to both Johan Santana, who was nearing a comeback, and Miguel Gonzalez has thrown up a number of possibilities with the starting rotation going forward. Having been inconsistent all season, the planned addition of Santana was hoped to add an element of consistency and reliability to a shaky group of starters. However, his season-ending Achilles injury, suffered while retrieving a batted ball during an extended spring training start on Friday, has put an end to that. On the same day, Gonzalez was placed on the 15-day disabled list, instead of risking him with a strained right oblique. In response, the Orioles called up Kevin Gausman from Triple-A Norfolk and he immediately impressed, allowing five baserunners and one run in seven innings of work against the Oakland Athletics on Saturday night. The 23-year-old's exciting outing has out him in position to claim a spot in the rotation and raised questions as to what the rotation should be moving forward. Do the O's proceed with six starters or does someone from the current group miss out? Chris Tillman has credit in the bank after fantastic seasons in 2012 and 2013, and he's lucky that he does. The struggles experienced this season may be the worst of his big league career and he's currently working to an ERA of 4.91. In the five games since his complete-game shutout against the Royals on May 16, Tillman has allowed 21 earned runs in 20 1/3 innings and on two occasions, he's been hooked before he could record an out in the second inning. Despite the major concerns this presents manager Buck Showalter, Tillman will be given plenty of opportunities to right the wrongs and at this stage, his spot in the rotation isn't in serious jeopardy. Ubaldo Jimenez, the big four-year, $50 million spring signing, has been disappointing thus far and through 13 games is working to a 5.01 ERA. Like Tillman, Jimenez has had control issues all season and has allowed far too many walks - 40 in total, which is the second most in the major leagues. Despite the struggles, too much has been invested for things to change yet and it's also well known that he often plays his best baseball later in the season. Wei-Yin Chen has been steady and despite his impressive record of 6-2, he's relied on some favorable run support to win games where he hasn't been at his best. Through 12 games, Chen's ERA of 4.13 is similar to that of his career mark (4.06), so it's hard to judge whether there is potential for more improvement as the season progresses. One positive of Chen's pitching is his control, having allowed just 11 walks all season. Though deserving of his spot in the rotation, his lack of free passes could be of benefit if he were to pitch in relief during the later innings. Bud Norris has been the standout of the rotation, having improved significantly since last season. Through 12 games, he is working to a 3.94 ERA and has comfortably been the Orioles pitcher most likely to go deeper into games - averaging just under 6 1/3 innings per outing. In eight of his 12 starts, he has lasted at least six innings and at this stage, he is one pitcher who certainly deserves to remain in the rotation. Gonzalez struggled early in the season, but just prior to his injury, he'd started to find some consistency. In his last four starts, Gonzalez had allowed just eight earned runs in 25 2/3 innings of work, which has brought his ERA back down to 4.17. He has been a significantly underrated performer since his debut in May 2012, working to a career ERA of 3.68, and has proven himself worthy of a rotation spot. All things considered, the six-man rotation could work for the O's and given the current lack of consistency and success from the five-man rotation, there's really nothing to lose from trying. Gonzalez and Chen are still relatively new to the rigors of a major league season and neither has pitched 200 innings in a season before. Their endurance and strength down the stretch are somewhat of an unknown and having a lighter workload over the next few months will certainly help keep their arms fresh for a potential playoff run. Having the extra arm available will also add some flexibility for long-relief outings or games that go an extended amount of extra-innings - something the O's have experienced a lot of since 2012. There's really no obvious downside to working with the six-man rotation and as such, I think it's probably the best move going forward for the O's at this stage. Daniel Clark blogs about the Orioles at The Big Leagues Daily from Melbourne, Australia. Follow him on Twitter: @DC_TBLDaily. His thoughts on the O's appear here as part of MASNsports.com's continuing commitment to welcome guest bloggers to our little corner of cyberspace. All opinions expressed are those of the guest bloggers, who are not employed by MASNsports.com but are just as passionate about their baseball as our roster of writers.