Alex Cobb has taken over the role of ace for the Tampa Bay Rays since the trade of former American League Cy Young Award winner David Price. Cobb goes for his career-high eighth straight victory and attempts to extend his unbeaten streak to 12 games when the Rays host the Boston Red Sox on Sunday in the third contest of their four-game series. Cobb has given up only six runs over his last seven starts and hopes to give Tampa Bay another gem after Jake Odorizzi's seven one-hit innings Saturday.Tampa Bay's playoff hopes have dwindled as it has won only five of its last 14 contests, including a 7-0 victory in the second game of the series. Evan Longoria has heated up for the Rays, going 12-for-37 with nine RBIs over his last nine games. Red Sox All-Star second baseman Dustin Pedroia left Saturday's game with symptoms consistent with a concussion after he was hit in the head inadvertently on a slide by Tampa Bay's Logan Forsythe, and is considered day-to-day.TV: 1:40 p.m. ET, NESN (Boston), Sun Sports (Tampa Bay)PITCHING MATCHUP: Red Sox RH Clay Buchholz (5-8, 5.77 ERA) vs. Rays RH Alex Cobb (9-6, 3.06)Buchholz is winless in seven consecutive outings, although he has allowed three or fewer runs and gone at least seven innings in three of his last four starts. The 30-year-old Texan has been better on the road, posting a 3-3 record and 4.56 ERA as opposed to 2-5 and 7.20 at home. Jose Molina is 7-for-22 against Buchholz, who is 7-5 with a 2.41 ERA in 16 career starts versus Tampa Bay.Cobb tries to add to his case for being selected American League Pitcher of the Month after going 2-0 with a 1.50 ERA in five August starts. The Boston native comes in off his second-shortest outing of the season, though, when he permitted two runs in four innings at Baltimore. Cobb has not faced the Red Sox this season but owns a 2-2 record against them in seven career starts with a 4.19 ERA.WALK-OFFS1. Tampa Bay CF Desmond Jennings has missed the last two games with a sore left knee but could return to the lineup Sunday.2. Boston DH David Ortiz has reached base in 15 straight games but is only 1-for-8 in the series and batting .180 against Tampa Bay in 2014.3. The Rays have committed an error in seven straight contests, their longest such streak since May 18-25, 2012 (seven games).PREDICTION: Rays 5, Red Sox 1