In his last three starts Lester has pitching 17.2 innings and surrendered 11 earned runs. Thats an ERA of 5.60. Prior to that he had pitched exactly four good game this year-following a year where he pitched poorly with an ERA of 4.82. His fastball velocity is down again this year to 91.9, down from 92.0 last year, which was down from 92.6 in 2011, which is down from 93.5 in 2010. See the pattern? Once a pitcher loses velocity off his fastball it is rarely regained, unless that loss is due to injury.
Unfortunately, he is far from out of the woods. Yes he had a fast start, but today's mediocre performance does little to inspire confidence in him. His prorated ERA for today was 4.50, which is very near the average ERA for the AL. Lester IMO is a serviceable #3 SP, but not more than that. Its certainly tempting to look at his first four games this year and get giddy about his "return to form", but his last three games clearly demonstrate that he is most certainly not out of the woods, no matter how much we all wish he were.