The early season experiment of having Scott Linebrink pitch the 7th is thankfully over. But, he can still provide value by pitching in lower leverage situations. It's easy to complain over Linebrink's effectiveness and demanding his release after last night's game, but in a long season it takes more time to decide if a player can no longer contribute. Remember, he came into last nights game in the 10th in a high pressure situation to get the last put against a right handed batter and got the out he needed. If the Braves had scored a run in the bottom frame, there might have been clamor that he's turning it around. As is turns out, he was wildly ineffective and got tagged for four runs and balooned his ERA to 7.50. Based on his career and peripheral statistics, he still deserves to prove he can help this team.
For relievers, using ERA doesn't make a whole of sense. ERA is scaled to 9 innings of work when relievers are used for short term duty, but more importantly relievers are prone to inherited and bequeathed runners. FIP is a useful measurement, but again in small sample sizes of relievers, home run rates take longer to normalize. It's better to use xFIP to gauge a reliever's performance. Even after last night's debacle, his xFIP is 4.01. The last three years his xFIP rates have been 4.01, 4.12, and 4.15. His career xFIP rate is 4.06. That's not great, but it can still help a team. Turner Field will help suppress home runs better than U.S. Cellular Field in Chicago, so his results can still improve. His BABIP this season is an unsightly .405. It's hard to imagine it being that high for very long and I expect that to be the peak rate. His K/9 rate is a laudable 9.00 and his BB/9 is only 2.25. Once he gets more innings, I would expect his results on the field to be more in line with his peripherals in this early season.
It'll likely be a while before Linebrink sees a high leverage situation again. In long or middle relief I expect his BABIP to go down and his ERA to follow suit. Every team in the MLB has guys in their bullpen who are fringe relievers that are not meant to pitch frequently in high leverage situations. Linebrink is one of those fringe relievers. Martinez is still the "long man" as he has shown his ability to pitch effectively in multiple inning appearances (like Game 1 against Washington). Linebrink's position should not be in a situation when the score is within 2 runs and better arms are available. Linebrink hasn't shown much of a plantoon split in his career, so he can pitch whole frames. Those frames should come when the situation isn't very dire. I didn't have any qualms about his coming into a tie game in extra innings because the only other reliever was Martinez (who just pitched 3 innings the night before). Once he does pitch, I expect his performance to improve and be more in line with his peripheral stats.